text:
Flytoget

The Airport Express Train (Flytoget) is a Norwegian high-speed airport railway service connecting Oslo Airport to Oslo Central Station in nineteen minutes. Run by Flytoget AS (formerly NSB Gardermobanen AS), it operates on the high-speed Gardermoen Line using sixteen GMB Class 71 electric trains. Normal service frequency is once every ten minutes, with five of the services each hour continuing westwards beyond Oslo Central. The extended services serve nine stops within Greater Oslo and take up to 60 minutes.

Flytoget transported 5.4 million passengers in 2007, a 34-percent market share of airport ground transport. The service, which has a top speed of 210 km/h, is the only high-speed rail service in Norway. Construction started in 1994 and high-speed trains began serving Gardermoen Airport from the date of its opening on 8 October 1998, although full operation using the 14.5 km Romerike Tunnel had to wait another ten and a half months after severe leaks caused by the tunnel's construction led to the partial depletion of two lakes.

Formed in 1992 as a subsidiary of Norwegian State Railways, the company has been owned since 2001 by the Norwegian Ministry of Trade and Industry.

Decision for a new airport connection
When the Parliament of Norway on 8 October 1992 decided to build a new central airport for Eastern Norway, they also decided that the main mode of ground transport should be by rail. While the previous airport, Oslo Airport, Fornebu, was located just outside the city limits, the new airport, Oslo Airport, Gardermoen, would be located 50 km north of the city, outside the reach of existing public transport. The principle of the airport construction was that it was not to be footed by the tax payers; the entire airport would be built with borrowed money through Oslo Lufthavn AS, a subsidiary of the Norwegian Airport Administration. The same principle was chosen for the airport rail link—the Norwegian State Railways (NSB) creating the limited company subsidiary NSB Gardermobanen AS, founded on 24 November 1992, to perform the construction of the line. It would be able to charge train operators using the line, channeling the payments to cover down payments and interest of the debt used to build the railway. Profit margin was estimated to 7.5%.

Construction
Oslo Airport, Gardermoen, is not on the Trunk Line that runs north from Oslo. With heavy traffic and many small stops until Lillestrøm, and continuing north as single track, the Trunk Line would have to be supplemented by a parallel double track from Oslo, with a new route north of Kløfta to Eidsvoll, the 16 km north of the airport allowing trains operating on the Dovre Line to Lillehammer and Trondheim to access the airport. The 64 km line was named the Gardermo Line.

The Gardermo Line was the second attempt to build high-speed rail in Norway, after the 35 km line from Ski to Moss on the Østfold Line. But no operation speeds exceeding 160 km/h are achieved there due to short distances and limitations to rolling stock, making Gardermobanen the first real high-speed railway line in Norway. Due to the domination of single track in Norway, the opening of the Gardermo Line increased the total length of double track in the kingdom by two-thirds.

Construction started in 1994. An agreement for purchase of sixteen three-car electric multiple units was signed with Adtranz on 23 February 1995. Parliament decided on 1 October 1996 that the construction company would also operate the new train service. The trains were delivered between 19 September 1997 and 30 January 1998, costing NOK 1.4 billion.

Challenges
The greatest challenge was the need to build the 14580 m Romerike railway tunnel – Norway's longest – beneath the geologically highly unstable Østmarka area between Etterstad, close to Oslo Central Station, and Lillestrøm. During construction, in 1997, the water level in some lakes above the tunnel, including Lutvann and Nordre Puttjern, sank dramatically. After the leaks were discovered on 3 February 1997, sanctions were imposed by the Norwegian Water Resources and Energy Directorate requiring the elimination of all leakages. At its worst, the tunnel was leaking 3000 L of water per minute.

Rhoca-Gil sealant was used in an attempt to fix the leaks, but failed to work properly. Not only did it not polymerise, and therefore failed to staunch the leaks, but it also poisoned its surroundings with acrylamide. Manual fixing with concrete became necessary; the fixing and cleaning up of the toxin delayed the building of the tunnel by one year. Further complications arose due to conflicts between NSB Gardermobanen and the construction company, Scandinavian Rock Group, with the latter at one instance stopping work for three weeks while the parties quarrelled in court.

Reports have shown a lack of inspection and reporting procedures during incidents that should have been addressed – but were never taken seriously – in 1995. Construction of the tunnel caused damage to around sixty houses and an evaluation by the Ministry of Transport and Communications showed that NOK 500 million was spent on fixing the leaks and claimed that this was to a large extent an unnecessary expenditure which more efficient engineering procedures would have avoided. The report also criticised the administrative planning and organisation of the overall construction of the railway.

Airport Express Trains began operating as soon as the new airport (and the Lillestrøm to Gardermoen stretch of the new high-speed line) opened on 8 October 1998; however, for more than ten months they had to use the old Hovedbane (Trunk Line) between Oslo S and Lillestrøm, which restricted their frequency to just two trains per hour. Regular operations at full capacity, using the Romerike Tunnel, did not commence until 22 August 1999.

Reorganisation
Estimates for the project costs were NOK 4.3 billion, ±20%, but by completion they had ended at NOK 7.7 billion, of which NOK 1.3 billion were related to the leakages. The rest of the line had a cost exceedings of NOK 0.4 billion. The company had acquired financial costs of NOK 0.9 billion, so the company owed NOK 10.0 billion by 1999, including money spent on the new trains.

The first steps of organisational restructure were taken 29 June 2000, when the CEO of NSB, Osmund Ueland, was fired due to several incidents related to the operations of NSB—not just the Gardermo Line. Einar Enger took over as new CEO on 26 February 2001.

The debt in NSB Gardermobanen had become unmanageable, and in April 2000 parliament accepted that it would not be possible to make the Gardermo Line—with the current structure—the profitable venture predicted in 1992. From 1 January 2001, the company changed name to Flytoget AS, retaining ownership of the trains and operations and kept as a subsidiary of NSB. The tracks and infrastructure were transferred to the Norwegian National Rail Administration (Jernbaneverket), who owns the rest of the Norwegian railway network. All debt was restored and covered by the state, and a vehicle excise duty was implemented on the Gardermo Line to cover the management and maintenance of the line, to be paid by all users.

On 9 December 2002, parliament decided that Flytoget AS would become a separate railway company from 1 January 2003, owned directly by the Ministry of Transport and Communications. One year later the ownership was transferred to the Ministry of Trade and Industry as part of a cleanup of political overhaul between the departments. As part of the process, a new CEO, Thomas Havnegjerde, was appointed in June 2002, and in January 2003 the new chair, Endre Skjørestad—who took over the position form NSB's director Einar Enger. Havnegjerde announced on 6 August 2008 that he would retire from his job before the end of the year. He was replaced by Linda Bernander Silseth on 10 November 2008. On 30 August 2009, two of three services to Asker were extended to Drammen. This followed upgrades to the Drammen Line, including the Lieråsen Tunnel, and a new parking lot at Drammen Station, in total costing NOK 20 million.

Operations
Departures operate every ten minutes from Oslo Central Station (Oslo S) to the airport - i.e. six trains per hour. Half of the trains originate in Drammen, making five intermediate stops before Oslo S, and again at Lillestrøm. One starts from Oslo S and goes directly to Gardermoen without intermediate stops. Two start from Stabekk with stops at Lysaker, Skøyen, Nationaltheateret and Oslo S. On Saturdays, Sunday mornings and during most of July, Flytoget does not operate the direct trains from Oslo S or Stabekk — only the 20-minute headway all-stop trains. While the services northeast from Oslo S to the airport use the high-speed Gardermo Line, those westwards towards Asker use the Drammen Line built in 1870–72 and the Asker Line; so while the 48 km from Oslo S to the airport can be done in 19 minutes, the 24 km from Asker to Oslo S takes 26 minutes. The latter does however include stops at five stations: Nationaltheatret, Skøyen, Lysaker, Sandvika and Asker.

Competition is offered from other means of ground transport and by Vy who operate trains from and to the airport. This includes one hourly departure with line R12 of the Oslo Commuter Rail north to Eidsvoll and south to Oslo, Drammen and Kongsberg; two regional trains (line RE10 and RE11) hourly north to Eidsvoll and Lillehammer and south to Drammen and Vestfold; and five daily express trains to Dombås and Trondheim calling Oslo Airport Station, including one night train (although the express trains to Trondheim do not accept passengers only travelling between Oslo and Gardermoen).

The price of a ticket to Oslo is NOK 230, though higher if departing from Sandvika, Asker and Drammen. Reduced fares with 50% discount are offered to senior citizens, children, youth under 21 years, students, benefit recipients and military personnel. Flytoget tickets are not valid on Vy trains, and vice versa. Vy tickets are generally cheaper, though not for some groups with reduced fare; for instance students are granted a greater discount with Flytoget than with Vy. Ticket can either be bought at vending machines or as e-tickets; there is no seat reservation.

Flytoget transported 5.4 million passengers in 2007, a 34% market share of airport ground transport. Flytoget boasts a high service quality, with 96% of departures arriving within 3 minutes of schedule and only 0.4% of departures canceled. Part of this is due to the airport express trains receiving priority over other trains in the limited capacity around Oslo. Flytoget was announced to have the most satisfied, and the fourth most loyal customers of all Norwegian companies in 2008, by the customer satisfaction survey conducted by the Norwegian School of Management. The same year Flytoget was declared the best place of work in Norway by Great Place to Work. During the 2007 recruitment half of the newly educated train drivers chose Flytoget over Vy, mostly due to higher wages.

Incidents
Several deaths have taken place on the route, but only one due to an accident. In 1999, an employee of the National Rail Administration was killed by a train because it was operating at 160 km/h instead of the temporarily reduced limit of 80 km/h; Flytoget was fined for not informing the engineer of the speed limit reduction. Several other deaths on the line have been classified as suicides, and so are not in the accident statistics; they do however cause delays on all services for hours after the incident takes place.

In 2000–01, Flytoget experienced three derailments with empty trains at Gardermoen; one caused by the engineer falling asleep and two by the train passing a red light. No more such accidents occurred after automatic Train Control was installed in 2001.

Delays have been experienced many times by travelers due to technical problems on the infrastructure. In particular the old line west of Oslo causes much delay, and the National Rail Administration performed during 2008 a NOK 100 million upgrade to the Oslo Tunnel to ensure better performance. But problems also incur on the new sections, regularly delaying service or capacity, and forcing Flytoget to operate fewer departures. In total 96% of departures arrived within 3 minutes of schedule and 0.4% of departures were canceled in 2007.

Pickpocketing has been a problem since the start; even the Chief of Police in Oslo has been robbed on the train. The train has also been the target of sabotage, and embezzlement for NOK 1 million by an employed ticket salesman, who found a way to print two tickets with the system only charging for one, by turning off and on the ticket printer.

When Al Gore came to Oslo to receive his Nobel Peace Prize on 7 December 2007, he used the Airport Express Train to make his journey as environmentally friendly as possible. The company has initiated a program to ensure better diet for the employees; this had made several lose weight and has reduced the level of sick leave from 12 to 8%. In 2005–07, a program to reduce the energy use of the trains through smarter operation reduced energy consumption by 15%.

During the 2010 volcano air travel disruption, the Gardermoen airport was closed for a period, and the Flytoget trains were used by NSB instead, to give extra train capacity for long-distance routes.

Class 71

The company operates sixteen Class 71 three-car electric multiple units delivered in 1997–98, and built domestically by Adtranz at Strømmen based on carbodies built in Adtranz factory in Kalmar. They are based on the Swedish X2 operated by SJ in their X 2000 intercity service, and developed by Kalmar Verkstad during the 1980s. The Class 71 are nearly identical to the NSB Class 73, save the 71-series lacking one car and tilting mechanism, and a different interior. Both have chosen to not use the original locomotive design, instead installing one powered bogie in each car. The 71-series is built for a maximum operating speed of 210 km/h, but has achieved higher speeds in test runs.

Among the features are pressure-tight cabins to allow comfortable travel through tunnels at high speeds, and step-free access to the cars. Instead, steps are inside the trains; this has been criticized to be in non-conformance with public accessibility policy. The multiple units can only operate in fixed sets of three cars, but up to three sets can be run in multiple. Flytoget regularly uses double sets to create six-car trains. In 2008–09, all units will be refit with an additional middle car by Bombardier Transportation, increasing capacity by 40% to 244 seats.

Unlike the Class 71, the sister trains in service with NSB were prone to trouble, having to operate on hundred-year-old infrastructure on cross-mountain services; the Class 71 has more lenient operating conditions thanks to better infrastructure. The only incident to ground all the BM71 trains occurred on the 17 June 2000 at Nelaug when a Class 73 train operated by NSB derailed because of stress on the axle. Unlike the NSB trains, the airport express trains were back in service the next day, while the 73-series had to wait another month. On 24 January 2004 a unit had to be taken out of service due to smoke from a stressed bearing—within days the bearings were replaced on all units.

Class 78
Flytoget purchased eight new 4-car CAF Oaris EMUs from the Spanish manufacturer CAF. They started operation in June 2021. Even though the EMU's maximum speed is 245 km/h, the infrastructure limits the speed to 210 km/h. The trainsets delivered to Flytoget were withdrawn from service after 19 days of operation due to discovery of cracks in the chassis.

New tracks
There are plans to build two more tracks from Lysaker to Oslo Central Station, including a new tunnel under central Oslo. This project is not decided.

title: Flytoget


text:
Underwater photography

Underwater photography is the process of taking photographs while under water. It is usually done while scuba diving, but can be done while diving on surface supply, snorkeling, swimming, from a submersible or remotely operated underwater vehicle, or from automated cameras lowered from the surface.

Underwater photography can also be categorised as an art form and a method for recording data. Successful underwater imaging is usually done with specialized equipment and techniques. However, it offers exciting and rare photographic opportunities. Animals such as fish and marine mammals are common subjects, but photographers also pursue shipwrecks, submerged cave systems, underwater "landscapes", invertebrates, seaweeds, geological features, and portraits of fellow divers.

Equipment
Some cameras are made for use underwater, including modern waterproof digital cameras. The first amphibious camera was the Calypso, reintroduced as the Nikonos in 1963. The Nikonos range was designed specifically for use underwater. Nikon ended the Nikonos series in 2001 and its use has declined, as has that of other 35mm film systems. Sea and Sea USA made the Motor Marine III, an amphibious range-finder camera for 35mm film.

Underwater housings
Cameras made for dry work can also work underwater, protected by add-on housings, which are made for point and shoot cameras, compact cameras with full exposure controls, and single lens reflex cameras (SLRs). Most such housings are specific to the camera model. Materials range from relatively inexpensive injection moulded plastic to higher-priced die-cast or machined from solid aluminum. Housings allow many options: users can choose housings specific to their everyday "land" cameras and use any lens, provided that it fits or they use the appropriate lens port accessory. Underwater photographers generally use wide-angle lenses or macro lenses, both of which allow close focus and therefore a shorter distance to the subject, which reduces the loss of clarity to scattering. Digital media can hold many more shots than standard film (which rarely has more than 36 frames per roll). This gives digital cameras an advantage, since it is impractical to change film underwater. Other comparisons between digital and film photography also apply, and the use of film under water has declined, as it has on land. It is also not possible to change regular lenses underwater, though some wet connectable telephoto, fisheye and macro extensions are available for some housings.

Underwater housings have control knobs and buttons that reach the camera inside, allowing use of most of its normal functions. These housings may also have connectors to attach external flash units. Some basic housings allow the use of the flash on the camera, but the on-board flash may not be powerful enough or properly placed for underwater use. More-advanced housings either redirect the on-board strobe to fire a slave strobe via a fiber-optic cable, or physically prevent the use of the on-board strobe. Housings are made waterproof by silicone or other elastomer O-rings at the closures and where control spindles and pushbuttons pass through the housing. High-end housings may use double O-rings on many of the critical pushbuttons and spindles to reduce the risk of leaks, which can destroy the electronics in cameras. Some cameras are inherently waterproof, or submersible to shallow depths; when these are in submersible housings, the consequences of a small leak are generally not serious.

There are optical problems with using cameras inside a watertight housing. Because of refraction, the image coming through the glass port will be distorted, especially with wide-angle lenses. A dome-shaped or fish-eye port corrects this distortion. Most manufacturers make these dome ports for their housings, often designing them to be used with specific lenses to maximize their effectiveness. The Nikonos series allowed the use of water-contact optics—lenses designed to be used submerged, without the ability to focus correctly when used in air. There is also a problem with some digital cameras, which do not have sufficiently wide lenses built in; to solve this, there are housings made with supplementary optics in addition to the dome port, making the apparent angle of view wider. Some housings work with wet-coupled lenses, which are screwed on to the outside of the lens port and increase the field of view; these lenses may be added or removed under water, allowing both macro and wide-angle photography on the same dive.

With macro lenses, the distortion caused by refraction is not a problem, so normally a simple flat glass port is used. Refraction through a flat port increases the magnification of a macro lens; this is considered a benefit to photographers who are trying to capture very small subjects. Digital cameras may have several user selectable or programmable modes, which may include modes specifically for underwater use. Buoyancy of the housing may have to be adjusted by adding ballast or buoyancy chambers. Ideally these should be incompressible at working depth range so the buoyancy remains constant throughout the dive. Most divers can manage a small divergence from neutral buoyancy, but a large divergence can make it difficult to hold the camera in place with one hand, which can often be useful, particularly with point and shoot cameras. When photographing on breathhold, it is convenient if the camera will float back to the surface if dropped. On scuba it may be more convenient if it does not float away.

Smartphone housings
Underwater housings for smartphones are available with a variety of depth ratings. Some are limited by operating system, for example, only for iOS, others are compatible with almost any phone that will physically fit into the housing, but require a specific app to be loaded on the phone so that it will communicate corrctly with the housing by bluetooth.Use of wireless communication between the housing and camera (smartphone) make it possible to make the housing with only one opening hull penetration and no moving parts penetrating the camera comartment. Some of these housings are pumped dowm to a near vacuum after sealing, which secures the cover and allows the seal to be tested before entering the water.

Camera formats
Most types of digital camera have some underwater application. Those commonly seen in use are the models for which stock underwater housings are available, or which are inherently waterproof, such as rugged compact cameras, which may be used at shallow depths without a housing, but have housings available for greater depths.
 * Compacts, rugged compacts and bridge cameras have great versatility regarding focal length, they tend to have a wide angle to telephoto lens with macro capabilities making these functions available without need to change lenses, which cannot be done during a dive. Although wet change accessories are available to increase or decrease focal length and for greater magnification, the 2020 generation rugged compacts already have inherent very close focus ability, and fairly wide angle low end of the focal length. Some of the rugged compact cameras will fit into a large dry suit or BC pocket in their underwater housing, though not usually with an external strobe or video light, allowing a diver to conveniently carry the camera on a working dive in case it may be useful, or for a larger format photographer to carry it as a backup, or for opportunities where the main camera has an unsuitable lens fitted.
 * Action cameras are popular with divers who want a record of the dive, but not the task loading of operating the camera controls. The camera can be hand held for versatility, or can be head mounted for first person view, or mounted on other equipment, like a diver propulsion vehicle.
 * Mirrorless interchangeable-lens cameras and Digital single-lens reflex cameras have very similar ranges of applications, mostly for high end work, where the photographer wants the best possible image quality, and has the skills and desire to put in the necessary effort and accepts the limitations of being stuck with the same lens throughout the dive, and managing bulky equipment. These formats are almost always used with large external lighting systems which are needed in most circumstances to get the best results. A relatively large capital investment in equipment is associated with the format.

Lighting

Lighting for underwater photography has several aspects. There may be insufficient natural light to take a photo, in many cases the natural light has lost a significant part of the spectrum, or the photographer wishes to emphasize contrast between foreground and background. Where flash is used for the actual photograph, auxiliary light may be necessary or desirable to facilitate composition and focusing in low light conditions. Many digital cameras have video options, which require a steady light source, and in some cases a single video light can provide all these functions, and also serve as an adequate dive light for non-photographic applications.

The primary obstacle faced by underwater photographers is the loss of color and contrast when submerged to any significant depth. The longer wavelengths of sunlight (such as red or orange) are absorbed quickly by the surrounding water, so even to the naked eye everything appears blue-green. The loss of color increases not only vertically through the water column, but also horizontally, so subjects farther away from the camera also appear colorless and indistinct. This effect occurs in apparently clear water, such as that found around tropical coral reefs.

Underwater photographers solve this problem by combining two techniques. The first is to get the camera as close to the photographic subject as possible, minimizing the horizontal loss of color. Many serious underwater photographers consider any more than about one yard or meter unacceptable. The second technique is the use of a flash or video lights to restore colour lost to depth. Fill flash, used effectively, "paints" in missing colors by providing full-spectrum visible light to the overall exposure.

Another environmental effect is range of visibility. The water is seldom optimally clear, and the dissolved and suspended matter can reduce visibility by both absorption and scattering of light.

Underwater flash
The use of a flash or strobe is often regarded as the most difficult aspect of underwater photography. Some misconceptions exist about the proper use of flash underwater, especially as it relates to wide-angle photography. Generally, the flash should be used to supplement the overall exposure and to restore lost color, not as the primary light source. In situations such as the interior of caves or shipwrecks, wide-angle images can be 100% strobe light, but such situations are fairly rare. Usually, the photographer tries to create an aesthetic balance between the available sunlight and the strobe. Deep, dark or low visibility environments can make this balance more difficult, but the concept remains the same. Many modern cameras have simplified this process through various automatic exposure modes and the use of through-the-lens (TTL) metering. The increasing use of digital cameras has reduced the learning curve of underwater flash significantly, since the user can instantly review photos and make adjustments.

Color is absorbed as it travels through water, so that the deeper the observer, the less reds, oranges and yellow colors remain. The strobe replaces that color. It also helps to provide shadow and texture, and is a valuable tool for creativity.

An added complication is the phenomenon of backscatter, where the flash reflects off particles in the water. Even seemingly clear water contains enormous amounts of these particulates, even if they not readily seen by the naked eye. The best technique for avoiding backscatter is positioning the strobe away from the axis of the camera lens. Ideally, this means the flash will not light up the particulates in water directly in front of the lens, but will still illuminate the subject. Various systems of jointed arms and attachments are used to make off-camera strobes easier to manipulate.

When using macro lenses, photographers are much more likely to use 100% strobe light for the exposure. The subject is normally very close to the lens, and the available ambient light is usually not sufficient.

There have been some attempts to avoid the use of artificial light entirely, but these have mostly failed. In shallow water, the use of custom white-balance provides excellent color without the use of strobe. In theory one could use color filters to overcome the blue-green shift, but this can be problematic. The amount of shift varies with depth and turbidity, and there would still be a significant loss of contrast. Many digital cameras have settings that will provide color balance, but this can cause other problems. For example, an image shifted toward the "warm" part of the spectrum can create background water which appears gray, purple or pink, and looks unnatural. There have been some successful experiments using filters combined with the raw image format function on some high-end digital cameras, allowing more detailed manipulation in the digital darkroom. This approach will probably always be restricted to shallower depths, where the loss of color is less extreme. In spite of that, it can be effective for large subjects such as shipwrecks which could not be lit effectively with strobes. Natural light photography underwater can be beautiful when done properly with subjects such as upward silhouettes, light beams, and large subjects such as whales and dolphins.

Although digital cameras have revolutionized many aspects of underwater imaging, it is unlikely that flash will ever be eliminated completely. From an aesthetic standpoint, the flash emphasizes the subject and helps separate it from the blue background, especially in deeper water. Ultimately the loss of color and contrast is a pervasive optical problem that cannot always be adjusted in software such as Photoshop.

Snoot
A snoot is a tube used to direct the illumination from the flash or other light source to a very restricted area, strongly illuminating the area of focus and leaving the surroundings relatively dark. It is used to selectively illuminate the subject to give dark backgrounds and a brightly lit subject. It is easier to use if the flash has an integral modeling light so the photographer can see how the illumination will be distributed during exposure. A snoot with the opening placed close to the subject at an angle can virtually eliminate backscatter.

Modeling lights
A modeling light is a low intensity light used to compose the picture when flash is intended for illumination. It allows a better view of the subject for focusing and framing the shot, but does not provide enough light to interfere with the flash illumination. Some flash units have integral modeling lights, otherwise a diffuse low power dive light may work well for close up work.

Video lights
A video light is a powerful light source used primarily for shooting video in environments with insufficient natural light, but can also be used as the primary light source for still photography. Placement of the video light follows the same recommendations as for flash photography, with the advantage that the illumination can be clearly seen and assessed before exposure. Considerably more energy is required for constant illumination in comparison with flash, and this method is best suited to cameras with sufficiently sensitive CCDs and for close up work. Another advantage is that the video light provides good illumination for general diving purposes. Video lights with adjustable intensity can be even more versatile. Video lights tend to be mounted similarly to flash. The intense light may disturb light sensitive animals, and they may react by retreating from the source. A large proportion of digital cameras have high definition video function, and video lights provide the option of switching between still and video using the same equipment.

Split images
Another format considered part of underwater photography is the over/under or split image, a composition that includes roughly half above the surface and half underwater, with both in focus. One of the pioneers of the traditional technique was National Geographic photographer David Doubilet, who used it to capture scenes above and below the surface simultaneously. Split images are popular in recreational scuba magazines, often showing divers swimming beneath a boat, or shallow coral reefs with the shoreline seen in the background.

Over/under shots present some technical challenges beyond the scope of most underwater camera systems. Normally an ultra wide angle lens is used, similar to the way it would be used in everyday underwater photography. However, the exposure value in the above water part of the image is often higher (brighter) than in the one underwater. There is also the problem of refraction in the underwater segment, and how it affects the overall focus in relation to the air segment. There are specialized split filters designed to compensate for both of these problems, as well as techniques for creating even exposure across the entire image.

However, professional photographers often use extremely wide or fisheye lenses that provide extensive depth of field - and a very small aperture for even more extensive depth of field; this is intended for acceptably sharp focus both on the nearby underwater subject and the more distant elements above water. An external flash can also be very useful underwater, on a low setting, to balance the light: to overcome the difference in brightness of the elements above and below the water.

Over/under photos necessitate the lens or port to be partly below and partly above the surface. When bringing the outer optical surface out of the water, droplets can be left on the surface which can distort the image. This can be avoided to some extent by wiping off the droplets with a chamois leather cloth above the water and lowering the camera to working position. Keeping the port fully wet is an alternative option, which requires the shot to be taken before the water on the top part of the lens surface separates into droplets. Which approach works better will depend on the surface tension of water on the lens surface.

David Doubilet explained his technique for split field images in an interview for Nikon Corporation. "You need to use a D-SLR and a super wide-angle or fisheye lens and a sophisticated housing that has a dome, not a flat port. Underwater images are magnified by 25 percent, and the dome will correct for that. The technique requires a small f/stop—f/16 or smaller—for great depth of field, plus a lens capable of close-focus; you always focus on the subject below the water line. You also have to balance the light. I look for a light bottom—white sand is best—or a light underwater subject. I'll put the strobes down below and light the bottom and then expose for the top. If you shoot at, say, ISO 400, you'll have plenty of exposure for the top, and the strobes will take care of the bottom. Of course, you need subjects that suit the technique."

Digital darkroom techniques can also be used to "merge" two images together, creating the appearance of an over/under shot.

Applications

 * Artistic photography, where the emotional impact on the viewer is a primary concern.
 * Records of the condition of equipment and structures by commercial divers, where the purpose is to accurately present visible evidence of the condition of the subject.
 * Records of the environment for personal and scientific purposes
 * Citizen science websites for recording Biodiversity using underwater photographs as records, such as iNaturalist, Reef Life Survey, iSpot etc., use photography as a reliable source of objective data where the observer is not required to be recognised as an expert in identification of the subject, but is trusted to provide sufficiently accurate information regarding time, location, and similar meta-data. Recreational diver photographic coverage of the underwater environment is much more frequent than scientific research capacity for popular dive sites.

Skills and training
Since underwater photography is often performed while scuba diving, it is important that the diver-photographer be sufficiently skilled so that it remains a reasonably safe activity. Good scuba technique also improves the quality of images, since marine life is less likely to be scared away by a calm diver, and the environment is less likely to be damaged or disturbed by a diver competent in buoyancy, trim, and maneuvering skills. There is the possibility of encountering poor conditions, such as heavy currents, tidal flow, or poor visibility. Underwater photographers usually try to avoid these situations if reasonably practicable, but in many cases the desired subject can only be accessed under less than ideal conditions and the photographer must deal with reality. Underwater diving training providers provide courses to help improve divers' diving skills and underwater photography skills. Good diving skills are necessary to avoid damaging the environment when maneuvering close to benthic subjects on reefs. Some underwater photographers have been implicated in reef damage.

Scientific potential
Underwater photography has become more and more popular since the early 2000s, resulting on millions of pictures posted every year on various websites and social media. This mass of documentation is endowed with an enormous scientific potential, as millions of tourists possess a much superior coverage power than professional scientists, who can not allow themselves to spend so much time in the field. As a consequence, several participative sciences programs have been developed, supported by geo-localization and identification web sites (such as iNaturalist), along with protocols for auto-organization and self-teaching aimed at biodiversity-interested snorkelers, in order for them to turn their observations into sound scientific data, available for research. This kind of approach has been successfully used in Réunion island, allowing for tens of new records and even new species.

Timeline

 * 1856 — William Thompson takes the first underwater pictures using a camera mounted on a pole.
 * 1893 — Louis Boutan takes underwater pictures in Banyuls-sur-Mer while diving using surface supplied standard diving dress. He also develops an underwater flash and a remote control for deep waters using an electromagnet.
 * 1914 — John Ernest Williamson shoots the first underwater motion picture in the Bahamas.
 * 1926 — William Harding Longley and Charles Martin take the first underwater colour photos using a magnesium-powered flash.
 * 1940- — Bruce Mozert begins to photograph at Silver Springs, Florida
 * 1948 — Development of the Rolleimarin medium format camera housing started on the request of Hans Hass.
 * 1954 — The Rolleimarin housing first marketed.
 * 1957 — The CALYPSO-PHOT camera is designed by Jean de Wouters and promoted by Jacques-Yves Cousteau. It is first released in Australia in 1963. It features a maximum 1/1000 second shutter speed. A similar version is later produced by Nikon as the Nikonos, with a maximum 1/500 second shutter speed and becomes the best-selling underwater camera series.
 * 1961 — The San Diego Underwater Photographic Society is established, one of the earliest organizations dedicated to the advancement of underwater photography.

Notable underwater photographers

 * Tamara Benitez – Filipina cinematographer
 * Christy Lee Rogers – Underwater fine art photographer
 * Georges Beuchat – French inventor, diver and businessman
 * Adrian Biddle – English cinematographer
 * Jonathan Bird – American photographer, cinematographer, director and television host.
 * Eric Cheng – Taiwanese American entrepreneur and professional photographer
 * Neville Coleman – Australian naturalist, underwater photographer, writer, publisher and educator
 * Jacques Cousteau – French inventor of open circuit scuba, pioneer diver, author, film-maker and marine researcher
 * John D. Craig – American businessman, writer, soldier, and diver
 * Ben Cropp – Australian documentary filmmaker, conservationist and spearfisherman
 * Bernard Delemotte – French diver and photographer
 * David Doubilet – French diver and photographer
 * John Christopher Fine – American marine biologist, wreck diver and author
 * Rodney Fox – Australian diver, film maker and conservationist
 * Ric Frazier – American photographer
 * Stephen Frink – Underwater photographer and publisher
 * Peter Gimbel – American filmmaker and underwater photojournalist
 * Monty Halls – British TV broadcaster, diver and naturalist
 * Hans Hass – Austrian biologist, film-maker, and underwater diving pioneer
 * Henry Way Kendall – American particle physicist who won the Nobel Prize in Physics
 * Rudie Kuiter – Dutch-born Australian underwater photographer, taxonomist, and marine biologist
 * Joseph B. MacInnis – Canadian physician, author, poet and aquanaut
 * Luis Marden – American photographer, explorer, writer, filmmaker, diver, navigator, and linguist
 * Agnes Milowka – Australian cave diver
 * Noel Monkman – New Zealand born Australian filmmaker specialising in underwater photography
 * Steve Parish – British born Australian photographer and publisher
 * Zale Parry – American pioneer scuba diver, underwater photographer and actress
 * Pierre Petit – Early French photographer. First to attempt underwater photography
 * Ronald C. Phillips – American marine botanist and professor. Produced coral and seagrass slides 1960s onwards for international scientific publications and university education
 * Leni Riefenstahl – German film director, producer, screenwriter, editor, photographer, actress and dancer
 * Peter Scoones – Underwater cameraman
 * Brian Skerry – American photojournalist
 * Wesley C. Skiles – American cave diver and underwater cinematographer
 * E. Lee Spence – underwater archaeologist
 * Philippe Tailliez – French pioneer of scuba diving and underwater photographer
 * Ron Taylor and Valerie Taylor – Australian divers and shark cinematographers
 * Albert Tillman – American educator and underwater diver.
 * John Veltri – American filmmaker and underwater photographer
 * Stan Waterman – Cinematographer and underwater film producer
 * J. Lamar Worzel – American geophysicist and underwater photographer

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Underwater photography


text:
Concerned Women for America

Concerned Women for America (CWA) is a socially conservative, evangelical Christian non-profit women's legislative action committee in the United States. Headquartered in Washington D.C., the CWA is involved in social and political movements, through which it aims to incorporate Christian ideology. The group is primarily led by well-funded anti-feminist interests.

The group was founded in San Diego, California in 1978 by Beverly LaHaye, whose husband Timothy LaHaye was an evangelical Christian minister and author of The Battle for the Mind, as well as coauthor of the Left Behind series.

The CWA identifies itself as an amalgam of "policy experts and... activists[s]" with an anti-feminist approach to politics.

Formation
Concerned Women for America is part of a movement known as the New Christian Right. Organized in reaction to the establishment of its liberal counterpart, the National Organization for Women; the growing dispute over traditional gender roles; and the rising discussion of the Equal Rights Amendment (ERA), the CWA set out to "fight policies that it believe[d] [to] disrupt traditional gender roles and norms." Fueling its formation, an interview between Barbara Walters and Betty Friedan, a prominent feminist activist, gained public attention in 1978 regarding women's issues. In the interview, Friedan claimed to speak for American women. Beverly LaHaye did not believe that Betty Friedan was speaking for the majority of women because feminist views were, according to LaHaye, anti-God and anti-family. In regards to the interview, LaHaye stated that she was convinced Friedan's goal was a "misguided attempt to dismantle the bedrock of American culture: the family," and that she believed Christian women were not included in discussions of women's rights. In this regard, the "concern" that the CWA had behind the name of the group was in response to the worries that feminism would "ruin" America. Such fears and opposition to much of the Democratic Party's ideology during this era led Beverly LaHaye to host a series of conventions and rallies in San Diego, resulting in Concerned Women for America's formation. As a result, the CWA became known as "the largest women's organization of the Christian Right during the 1980s and 1990s."

The CWA began with local prayer chapters mobilized around issues such as the ERA and legalized abortion. In 1987, the CWA relocated from San Diego, California to Washington, DC, at which time it formally established a national office and a national presence.

Issues
The CWA identifies itself as an organization in opposition to feminism that speaks for evangelical women who feel that the national feminist movement does not support their interests. The CWA has taken strong conservative stances on several highly debated matters. The CWA has publicly stated its opposition to issues such as abortion, sex education, same-sex marriage, euthanasia, embryonic stem cell research, needle exchange programs, pornography, cloning, drug abuse, secular education, gambling, or any other efforts which "intervene with natural human life." The organization's stance on contraception is not as clear, however, for members’ opinions on this topic vary widely. The only definite statement the CWA has put forth in regards to contraception is that its stance, as a whole, is ambiguous, but that "many Catholic women follow the church’s teaching on the use of contraceptives." The CWA focuses on promoting its conservative, Christian-based ideology through seven "core issues".

Abortion
A few years prior to the organization's founding, the Supreme Court released its decisions regarding Roe v. Wade and Doe v. Bolton, which granted women the right to attain an abortion, and disbanded all state laws restricting such action. Because many of the CWA's members were supporters of the Right to Life Movement and strongly opposed these rulings, Concerned Women for America is recognized as an anti-abortion organization. At the time of its founding, the CWA, along with similar organizations which spawned during this era, identified itself as part of the "pro-family movement," arguing that abortion defied both Christian morality and traditional family values.

The CWA was a proponent of the welfare revisions set out by the 1994 "Contract with America", which aimed to reduce the frequency and acceptance of illegitimate (out of wedlock) births. These revisions suggested (1) incentivizing states to "reduce illegitimate births without...increas[ing] abortions" by way of block grants; (2) denying monetary assistance to "children born to unmarried minor mothers;" and (3) establishing a "family cap" in which unwed mothers could only be compensated for one child, all of which the CWA supported due to its strong opposition to abortion and its defense of the traditional family, as discussed below.

Currently, the CWA strives to inform the public of the harm it claims that abortion has on men, women and their families. The CWA began using the common anti-abortion movement's rhetoric of protecting women and their health in the mid-1990s, as a way to promote interest in the anti-abortion movement. The CWA lobbies for defunding domestic and international family planning programs, especially those that perform abortions or provide Norplant. The CWA supports crisis pregnancy centers and post-abortion counseling services.

The CWA opposes emergency contraception, such as Plan B, on the grounds that it "blurs the line" between contraception and abortion.

Marriage
As a supporter of traditional gender roles and the nuclear family, the CWA publicly defends western familialism and the subservience of women. As such, the CWA is a supporter of the sanctity of marriage and reproduction, and strongly opposes divorce.

Regarding the defense of the family, the CWA was a latecomer to the opposition of the ERA. The CWA believes that the woman's place is within the home, therefore the rights set forth by the ERA threatened the traditional nuclear family. The CWA built a national network of prayer chains in opposition to the ERA. The CWA was a supporter of the Defense of Marriage Act as DOMA declared homosexual marriages to be illegal, thus supporting the CWA's ideals of both heterosexuality and marriage.

The CWA believes it is a Christian's duty to start a family, explaining their general disapproval of those who do not wish to have children. More specifically, these familial ideals tie into the CWA's understanding of women and motherhood; as expressed by founder Beverly LaHaye, women have a "natural" desire to be mothers, leading to the organization's encouragement of women's domesticity through stay-at-home motherhood.

The CWA opposed the 1988 Act for Better Child Care (H.R. 3660), which would have provided government-sponsored child care for families in which both parents are working. The CWA also testified against the Family and Medical Leave Act of 1993 on the premise that it was biased against those who could not afford to take leave.

In support of these ideals, the CWA opposes pornography, believing that consumption of such media can disrupt traditional family values, as well as promote domestic violence. More specifically, the CWA "contends that pornography persuades men to demean their wives, to ruin their marriages, and to engage in illicit sexual behaviors". In addition, the CWA claims that the proliferation of and lack of regulation for pornography promotes gay rights and premarital sex, both of which it strongly opposes.

Religious education in public schools
Being a Christian organization, the CWA is known to promote Christian teachings in schools. The CWA believes that they must defend "God's truth," and to do so, they advocate against "secular humanist" teachings and influence in public education. It is for these reasons that the CWA initially gained recognition as a public policy organization, for it publicly opposed the U.S. Supreme Court's rulings in 1962 and 1963, which banned religious teachings and practices, such as prayers and Bible readings, in public schools.

To provide a more historical context of the organization's educational efforts, in 1983, the CWA's desire for a combination of fundamental and religious teachings was concretely displayed through a lawsuit, known today as Mozert v. Hawkins County Board of Education, which arose between parents (members of the CWA) and a local Tennessee school board. The case began when a local mother, Vicki Frost, reprimanded the administration at her daughter's school for providing students with books that discussed evolution, feminism, and telepathy, which she contended "could turn children away from God." The dispute quickly escalated as a group of likeminded parents joined Frost and filed a federal lawsuit, resulting in the CWA's public support against the school and People for the American Way, one of its many liberal counterparts. Fearing the growth of the "Religious New Right," the CWA claimed that students should have the right to freely exercise their religion, parents should have a voice in their child's education, and there should be greater control over schools as a whole, arguments which gained favor in the trial court in 1986. To the CWA's dismay, however, U.S. Court of Appeals for the Sixth Circuit reversed this decision in 1987.

The CWA believes that sex education should not be taught in school, and that parents should be empowered to teach their own children about sex. However, they also concede that if it is taught in school, then it needs to be abstinence-only sex education. Many "sexual conservatives," as Lisa McGirr refers to them in her research regarding sex education, have relied on the CWA to help them implement such ideology into the development or modification of sex education programs in schools, as well as to provide educational speakers.

CWA supports teaching intelligent design in public schools and advocates school prayer, saying in a 1988 book titled America: To Pray or Not To Pray?, that since the Engel v. Vitale Supreme Court case of 1962 outlawed government-directed prayer, morality has declined in public schools and in society in general. As described above, the CWA aided the plaintiff in the 1983 case Mozert v. Hawkins, by arguing it is unconstitutional for public schools to require reading material that conflicts with the religious values of parents.

In similar fashion to the Mozert case, the CWA was recognized for its support of Nathan Bishop Middle School and the Providence, Rhode Island school district in the 1992 Lee v. Weisman case. Contrary to Mozert v. Hawkins, in which the CWA protested against the school's nonsecular teaching, Lee v. Weisman resulted in support from conservative Christian organizations, such as the CWA, who fought to defend the maintenance of religious practices in public schools, such as prayer at graduation.

Along with its support of the welfare revisions in the Contract with America, the CWA advocated for other amendments, such as the reinstitution of state-sponsored school prayer and "the eligibility of religious programs for public funding."

National sovereignty
The CWA originally opposed the U.S. involvement in the United Nations, but have since accepted the UN and instead focus on the alleged dangers of conferences and treaties. The CWA has more influence in international affairs than many other conservative organizations because they are active in the UN.

The CWA opposed CEDAW, The Convention on the Elimination of all Forms of Discrimination Against Women, which was adopted by the UN in 1979. They view CEDAW as a tool to undermine the traditional family and guarantee global abortion and prostitution.

Sexual exploitation
The CWA believes that men becoming addicted to pornography leads to the exploitation and victimization of women.

In addition to pornography, the CWA opposes prostitution. The CWA believes that legalizing prostitution would increase sex trafficking, not decrease it as other organizations have proposed.

The CWA has been actively involved in the prevention of sex trafficking; working closely with the National Organization for Women, the Family Research Council, Catholics for a Free Choice, Gloria Steinem, and Chuck Colson, the CWA has increased awareness of this issue, and was a major contributor in the establishment of The Trafficking Victims Protection Act (TVPA) in 2000.

In response to Google and Mozilla's plans to test a standard which would encrypt the Domain Name System, which could possibly impede internet surveillance by law enforcement, a CWA spokesperson said "We believe it is important for all stakeholders in the internet ecosystem to work together to ensure that encrypted DNS does not lead to unintended consequences that harm our children."

Support for Israel
On 8 May 2013 CWA's board of directors voted unanimously to include support for Israel as part of its core mission. CWA says it will support "laws and policies that strengthen the ties between Israel and the U.S." and "Policies enacted by our State Department, Department of Defense and others that encourage the development of our relationship with Israel.” Penny Nance said that support from CWA's founder, Beverly LaHaye, was the biggest driver behind the group formalizing its support for Israel. This relationship is backed by a long history of conservative Christians' support for Israel.

Project 2025
CWA is a member of the advisory board of Project 2025, a collection of conservative and right-wing policy proposals from the Heritage Foundation to reshape the United States federal government and consolidate executive power should the Republican nominee win the 2024 presidential election.

President/CEO

 * Carmen Pate, President 1996–1999
 * Wendy Wright, President 2006–2013
 * Penny Young Nance, CEO (2010–2013) and President 2013–present
 * Nance was previously a Federal Communications Commission advisor on children's social and media concerns.

Working through the media
In the late 1990s, the CWA garnered attention by way of its midday broadcasts on KFAX, a San Francisco-based Christian radio station. These broadcasts often featured Beverly LaHaye Live, a popular talk-show segment which spoke about the CWA's mission, morals, and aspirations for society. Today, the CWA continues to produce a daily radio show, however it is now entitled Concerned Women Today, and focuses primarily on calling members and other listeners to action by encouraging them to lobby senators.

The CWA publishes a monthly magazine called Family Voice, which chronicles their current events as well as ways in which members can become more involved with the organization.

Beverly LaHaye Institute
The Beverly LaHaye Institute (BLI), named for the CWA founder, is the research arm of the CWA. BLI is considered one of the CWA's official think tanks. The BLI has a variety of research style essays and briefs that cover a wide variety of topics the CWA is interested in, most of which is published or featured on the CWA website.

BLI filed an amicus brief in January 2014 in Sebelius vs. Hobby Lobby. Most of the amicus briefs in the Hobby Lobby case focused on religious freedom issues. BLI's brief had a unique focus on rebutting the government's argument that the birth control mandate imposed by Affordable Care Act would improve women's health and prevent unintended pregnancies. The BLI brief rejected a clear-cut notion of "intended" and "unintended" pregnancies. BLI argued that the government's evidence, based mostly on a 2011 Institute of Medicine report, did not prove the birth control mandate would increase use rates for birth control or that unintended pregnancies harm women's health. The brief also argued against the government's claim that the mandate promotes "gender equity."

Culture and Family Institute
The Culture and Family Institute is one of two of the CWA's research facilities. The Culture and Family Institute, founded in 2001, is a think tank that focuses exclusively on opposition to gay rights activism.

title: Concerned Women for America


text:
Night diving

Night diving is underwater diving done during the hours of darkness. It frequently refers specifically to recreational diving which takes place in darkness. The diver can experience a different underwater environment at night, because many marine animals are nocturnal.

There are additional hazards when diving in darkness, such as dive light failure. This can result in losing vertical visual references and being unable to control depth or buoyancy, being unable to read instruments such as dive computers and diving cylinder contents gauges, and potential separation from the rest of the diving group, boat, or shore cover. Even with a functioning light, these hazards are still present in night diving. Backup lights are recommended.

Training and certification
Several diver certification agencies offer specialty training in night diving,   and it was originally part of the training requirement for the second level of recreational diving (CMAS two-star scuba diver, etc.), but professional diver training will usually include it in entry-level training as it is considered a normal part of occupational diving.

Equipment and procedures
Normal requirements for night diving are a dive light, and adequate protection from exposure. Some precautions and skills for night diving include: avoiding shining the light in other divers' eyes, to be aware of and use surface light signals for bearings, and if appropriate to use an illuminated shotline buoy. A surface marker buoy with an attached strobe light or cyalume stick can be used to indicate the position of the divers to the surface team. The use of a strobe light by a diver under water can damage the night vision of other divers, and would generally be reserved as an emergency signal. A backup light can be useful if the primary light fails, and is essential if doing a decompression dive without a dive computer which can be read in the dark.

There are several advantages to night diving at a site that is familiar from diving there during the day. The diver who is more familiar with the site is less likely to be disoriented.

Excessively strong lights can scare off or stress nocturnal animals. and may make them more vulnerable to predation while regaining their vision. Similarly, divers will be dazzled by lights shone in their eyes, and will take some time to recover night vision, during which they will be less able to deal with contingencies. Dive light discipline is more difficult in larger groups.

Black-water diving is the night time equivalent of blue-water diving which is mid-water diving in deep open oceanic waters.

Recovering divers
If a diver surfaces away from the boat, dive lights can be used to signal the dive boat. A surface marker buoy can be illuminated with a dive light at night to increase the visibility of the dive team to the boat. Reflective tape surfaces can also be used to increase visibility of the team on the surface.

title: Night diving


text:
Superessive case

In grammar, the superessive case (abbreviated ) is a grammatical case indicating location on top of, or on the surface of something. Its name comes from Latin supersum, superesse: to be over and above. While most languages communicate this concept through the use of adpositions, there are some, such as Hungarian, which make use of cases for this grammatical structure.

An example in Hungarian: a könyveken means "on the books", literally "the books-on".

In Finnish, superessive is a case in the adverbial cases category, that are productive only with a limited set of stems. The superessive is marked with the -alla/-ällä ending. For example:

 * kaikkialla means "everywhere" (lit. "everything-at")

 * täällä means "(at) here" (from tämä - "this", lit. "at this place")

 * muualla means "(at) somewhere else" (from muu - "other", lit. "other-at")

In Lezgian, the superessive case is marked with suffixes: sew-re-l 'on the bear'.

title: Superessive case


text:
Depreciation

In accountancy, depreciation is a term that refers to two aspects of the same concept: first, an actual reduction in the fair value of an asset, such as the decrease in value of factory equipment each year as it is used and wears, and second, the allocation in accounting statements of the original cost of the assets to periods in which the assets are used (depreciation with the matching principle).

Depreciation is thus the decrease in the value of assets and the method used to reallocate, or "write down" the cost of a tangible asset (such as equipment) over its useful life span. Businesses depreciate long-term assets for both accounting and tax purposes. The decrease in value of the asset affects the balance sheet of a business or entity, and the method of depreciating the asset, accounting-wise, affects the net income, and thus the income statement that they report. Generally, the cost is allocated as depreciation expense among the periods in which the asset is expected to be used.

Accounting concept
In determining the net income (profits) from an activity, the receipts from the activity must be reduced by appropriate costs. One such cost is the cost of assets used but not immediately consumed in the activity. Such cost allocated in a given period is equal to the reduction in the value placed on the asset, which is initially equal to the amount paid for the asset and subsequently may or may not be related to the amount expected to be received upon its disposal. Depreciation is any method of allocating such net cost to those periods in which the organization is expected to benefit from the use of the asset. Depreciation is a process of deducting the cost of an asset over its useful life. Assets are sorted into different classes and each has its own useful life. The asset is referred to as a depreciable asset. Depreciation is technically a method of allocation, not valuation, even though it determines the value placed on the asset in the balance sheet.

Any business or income-producing activity using tangible assets may incur costs related to those assets. If an asset is expected to produce a benefit in future periods, some of these costs must be deferred rather than treated as a current expense. The business then records depreciation expense in its financial reporting as the current period's allocation of such costs. This is usually done in a rational and systematic manner. Generally, this involves four criteria:
 * Cost of the asset
 * Expected salvage value, also known as the residual value of the assets
 * Estimated useful life of the asset
 * A method of apportioning the cost over such life

Depreciable basis
Cost generally is the amount paid for the asset, including all costs related to acquiring and bringing the asset into use. In some countries or for some purposes, salvage value may be ignored. The rules of some countries specify lives and methods to be used for particular types of assets. However, in most countries the life is based on business experience, and the method may be chosen from one of several acceptable methods.

Impairment
Accounting rules also require that an impairment charge or expense be recognized if the value of assets declines unexpectedly. Such charges are usually nonrecurring and may relate to any type of asset. Many companies consider write-offs of some of their long-lived assets because some property, plant, and equipment have suffered partial obsolescence. Accountants reduce the asset's carrying amount by its fair value. For example, if a company continues to incur losses because prices of a particular product or service are higher than the operating costs, companies consider write-offs of the particular asset. These write-offs are referred to as impairments. There are events and changes in circumstances might lead to impairment. Some examples are: Events or changes in circumstances indicate that the company may not be able recover the carrying amount of the asset. In which case, companies use the recoverability test to determine whether impairment has occurred. The steps to determine are:
 * Large amount of decrease in fair value of an asset
 * A change of manner in which the asset is used
 * Accumulation of costs that are not originally expected to acquire or construct an asset
 * A projection of incurring losses associated with the particular asset

 * 1) Estimate the future cash flow of asset (from the use of the asset to disposition)
 * 2) If the sum of the expected cash flow is less than the carrying amount of the asset, the asset is considered impaired

Depletion and amortization
Depletion and amortization are similar concepts for natural resources (including oil) and intangible assets, respectively.

Effect on cash
Depreciation expense does not require a current outlay of cash. However, since depreciation is an expense to the P&L account, provided the enterprise is operating in a manner that covers its expenses (e.g., operating at a profit) depreciation is a source of cash in a statement of cash flows, which generally offsets the cash cost of acquiring new assets required to continue operations when existing assets reach the end of their useful lives.

Accumulated depreciation
While depreciation expense is recorded on the income statement of a business, its impact is generally recorded in a separate account and disclosed on the balance sheet as accumulated under fixed assets, according to most accounting principles. Accumulated depreciation is known as a contra account, because it separately shows a negative amount that is directly associated with an accumulated depreciation account on the balance sheet. Depreciation expense is usually charged against the relevant asset directly. The values of the fixed assets stated on the balance sheet will decline, even if the business has not invested in or disposed of any assets. Theoretically, the amounts will roughly approximate fair value. Otherwise, depreciation expense is charged against accumulated depreciation. Showing accumulated depreciation separately on the balance sheet has the effect of preserving the historical cost of assets on the balance sheet. If there have been no investments or dispositions in fixed assets for the year, then the values of the assets will be the same on the balance sheet for the current and prior year (P/Y).

Methods for depreciation
There are several methods for calculating depreciation, generally based on either the passage of time or the level of activity (or use) of the asset.

Straight-line depreciation
Straight-line depreciation is the simplest and most often used method. The straight-line depreciation is calculated by dividing the difference between assets pagal sale cost and its expected salvage value by the number of years for its expected useful life. (The salvage value may be zero, or even negative due to costs required to retire it; however, for depreciation purposes salvage value is not generally calculated at below zero.) The company will then charge the same amount to depreciation each year over that period, until the value shown for the asset has reduced from the original cost to the salvage value.

Straight-line method:
 * $$\mbox{annual depreciation expense} = {\mbox{cost of fixed asset} - \mbox{residual value} \over \mbox{useful life of asset} (years)}$$

DE=(Cost-SL)/UL

For example, a vehicle that depreciates over 5 years is purchased at a cost of $17,000 and will have a salvage value of $2000. Then this vehicle will depreciate at $3,000 per year, i.e. (17-2)/5 = 3. This table illustrates the straight-line method of depreciation. Book value at the beginning of the first year of depreciation is the original cost of the asset. Book value equals original cost minus accumulated depreciation.

book value = original cost − accumulated depreciation Book value at the end of year becomes book value at the beginning of next year. The asset is depreciated until the book value equals scrap value.

If the vehicle were to be sold and the sales price exceeded the depreciated value (net book value) then the excess would be considered a gain and subject to depreciation recapture. In addition, this gain above the depreciated value would be recognized as ordinary income by the tax office. If the sales price is ever less than the book value, the resulting capital loss is tax-deductible. If the sale price were ever more than the original book value, then the gain above the original book value is recognized as a capital gain.

If a company chooses to depreciate an asset at a different rate from that used by the tax office, then this generates a timing difference in the income statement due to the difference (at a point in time) between the taxation department's and company's view of the profit.

Diminishing balance method
The double-declining-balance method, or reducing balance method, is used to calculate an asset's accelerated rate of depreciation against its non-depreciated balance during earlier years of assets useful life. When using the double-declining-balance method, the salvage value is not considered in determining the annual depreciation, but the book value of the asset being depreciated is never brought below its salvage value, regardless of the method used. Depreciation ceases when either the salvage value or the end of the asset's useful life is reached.

Since double-declining-balance depreciation does not always depreciate an asset fully by its end of life, some methods also compute a straight-line depreciation each year, and apply the greater of the two. This has the effect of converting from declining-balance depreciation to straight-line depreciation at a midpoint in the asset's life. The double-declining-balance method is also a better representation of how vehicles depreciate and can more accurately match cost with benefit from asset use. The company in the future may want to allocate as little depreciation expenses as possible to help with additional expenses.

With the declining balance method, one can find the depreciation rate that would allow exactly for full depreciation by the end of the period, using the formula:

$$\mbox{depreciation rate} = 1 - \sqrt[N]{\mbox{residual value} \over \mbox{cost of fixed asset}}$$,

where N is the estimated life of the asset (for example, in years).

Annuity depreciation
Annuity depreciation methods are not based on time, but on a level of Annuity. This could be miles driven for a vehicle, or a cycle count for a machine. When the asset is acquired, its life is estimated in terms of this level of activity. Assume the vehicle above is estimated to go 50,000 miles in its lifetime. The per-mile depreciation rate is calculated as: ($17,000 cost - $2,000 salvage) / 50,000 miles = $0.30 per mile. Each year, the depreciation expense is then calculated by multiplying the number of miles driven by the per-mile depreciation rate.

Sum-of-years-digits method
Sum-of-years-digits is a spent depreciation method that results in a more accelerated write-off than the straight-line method, and typically also more accelerated than the declining balance method. Under this method, the annual depreciation is determined by multiplying the depreciable cost by a schedule of fractions.

Sum of the years' digits method of depreciation is one of the accelerated depreciation techniques which are based on the assumption that assets are generally more productive when they are new and their productivity decreases as they become old. The formula to calculate depreciation under SYD method is:

SYD depreciation = depreciable base x (remaining useful life/sum of the years' digits) depreciable base = cost − salvage value

Example: If an asset has original cost of $1000, a useful life of 5 years and a salvage value of $100, compute its depreciation schedule.

First, determine the years' digits. Since the asset has a useful life of 5 years, the years' digits are: 5, 4, 3, 2, and 1.

Next, calculate the sum of the digits: 5+4+3+2+1=15

The sum of the digits can also be determined by using the formula (n2+n)/2 where n is equal to the useful life of the asset in years. The example would be shown as (52+5)/2=15

Depreciation rates are as follows:

5/15 for the 1st year, 4/15 for the 2nd year, 3/15 for the 3rd year, 2/15 for the 4th year, and 1/15 for the 5th year.

Units-of-production depreciation method
Units-of-production depreciation method calculates greater deductions for depreciation in years when the asset is heavily used

 * $$\mbox{annual depreciation expense} = {\mbox{cost of fixed asset} - \mbox{residual value} \over \mbox{estimated total production}} \times \mbox{actual production}$$

DE= ((OV-SV)/EPC) x Units per year

Suppose an asset has original cost $70,000, salvage value $10,000, and is expected to produce 6,000 units.

Depreciation per unit = ($70,000−10,000) / 6,000 = $10

10 × actual production will give the depreciation cost of the current year.

The table below illustrates the units-of-production depreciation schedule of the asset.

Depreciation stops when book value is equal to the scrap value of the asset. In the end, the sum of accumulated depreciation and scrap value equals the original cost.

Group depreciation method
The group depreciation method is used for depreciating multiple-asset accounts using a similar depreciation method. The assets must be similar in nature and have approximately the same useful lives.

Composite depreciation method
The composite method is applied to a collection of assets that are not similar and have different service lives. For example, computers and printers are not similar, but both are part of the office equipment. Depreciation on all assets is determined by using the straight-line-depreciation method. Composite life equals the total depreciable cost divided by the total depreciation per year. $5,900 / $1,300 = 4.5 years.

Composite depreciation rate equals depreciation per year divided by total historical cost. $1,300 / $6,500 = 0.20 = 20%

Depreciation expense equals the composite depreciation rate times the balance in the asset account (historical cost). (0.20 * $6,500) $1,300. Debit depreciation expense and credit accumulated depreciation.

When an asset is sold, debit cash for the amount received and credit the asset account for its original cost. Debit the difference between the two to accumulated depreciation. Under the composite method, no gain or loss is recognized on the sale of an asset. Theoretically, this makes sense because the gains and losses from assets sold before and after the composite life will average themselves out.

To calculate composite depreciation rate, divide depreciation per year by total historical cost. To calculate depreciation expense, multiply the result by the same total historical cost. The result will equal the total depreciation per year again.

Common sense requires depreciation expense to be equal to total depreciation per year, without first dividing and then multiplying total depreciation per year by the same number.

Tax depreciation
Most income tax systems allow a tax deduction for recovery of the cost of assets used in a business or for the production of income. Such deductions are allowed for individuals and companies. Where the assets are consumed currently, the cost may be deducted currently as an expense or treated as part of cost of goods sold. The cost of assets not currently consumed generally must be deferred and recovered over time, such as through depreciation. Some systems permit the full deduction of the cost, at least in part, in the year the assets are acquired. Other systems allow depreciation expense over some life using some depreciation method or percentage. Rules vary highly by country and may vary within a country based on the type of asset or type of taxpayer. Many systems that specify depreciation lives and methods for financial reporting require the same lives and methods be used for tax purposes. Most tax systems provide different rules for real property (buildings, etc.) and personal property (equipment, etc.).

 * Reduce Taxable Income: Claiming tax depreciation lowers your taxable income. This can significantly reduce your tax bill, effectively putting more money back in your pocket each year.
 * Improve Cash Flow: By reducing your tax liability, you effectively increase your annual cash flow. This can be particularly beneficial for property investors who rely on rental income.
 * Maximize Investment Return: Depreciation is a non-cash deduction – it doesn’t come out of your pocket on an annual basis. Claiming it ensures you’re maximizing the return on your investment property.
 * Property Value Appreciation: Even as your property appreciates in market value, you can still claim depreciation on the building and its fixtures and fittings, enhancing the investment’s profitability.

Capital allowances
A common system is to allow a fixed percentage of the cost of depreciable assets to be deducted each year. This is often referred to as a capital allowance, as it is called in the United Kingdom. Deductions are permitted to individuals and businesses based on assets placed in service during or before the assessment year. Canada's Capital Cost Allowance are fixed percentages of assets within a class or type of asset. Fixed percentage rates are specified by the type of asset. The fixed percentage is multiplied by the tax basis of assets in service to determine the capital allowance deduction. The tax law or regulations of the country specifies these percentages. Capital allowance calculations may be based on the total set of assets, on sets or pools by year (vintage pools) or pools by classes of assets... Depreciation has got three methods only.

Tax lives and methods
Some systems specify lives based on classes of property defined by the tax authority. Canada Revenue Agency specifies numerous classes based on the type of property and how it is used. Under the United States depreciation system, the Internal Revenue Service publishes a detailed guide which includes a table of asset lives and the applicable conventions. The table also incorporates specified lives for certain commonly used assets (e.g., office furniture, computers, automobiles) which override the business use lives. U.S. tax depreciation is computed under the double-declining balance method switching to straight line or the straight-line method, at the option of the taxpayer. IRS tables specify percentages to apply to the basis of an asset for each year in which it is in service. Depreciation first becomes deductible when an asset is placed in service.

Additional depreciation
Many systems allow an additional deduction for a portion of the cost of depreciable assets acquired in the current tax year. The UK system provides a first-year capital allowance of £50,000. In the United States, two such deductions are available. A deduction for the full cost of depreciable tangible personal property is allowed up to $500,000 through 2013. This deduction is fully phased out for businesses acquiring over $2,000,000 of such property during the year. In addition, additional first year depreciation of 50% of the cost of most other depreciable tangible personal property is allowed as a deduction. Some other systems have similar first year or accelerated allowances.

Real property
Many tax systems prescribe longer depreciable lives for buildings and land improvements. Such lives may vary by type of use. Many such systems, including the United States, permit depreciation for real property using only the straight-line method, or a small fixed percentage of the cost. Generally, no depreciation tax deduction is allowed for bare land. In the United States, residential rental buildings are depreciable over a 27.5 year or 40-year life, other buildings over a 39 or 40-year life, and land improvements over a 15 or 20-year life, all using the straight-line method.

Averaging conventions
Depreciation calculations require a lot of record-keeping if done for each asset a business owns, especially if assets are added to after they are acquired, or partially disposed of. However, many tax systems permit all assets of a similar type acquired in the same year to be combined in a "pool". Depreciation is then computed for all assets in the pool as a single calculation. These calculations must make assumptions about the date of acquisition. The United States system allows a taxpayer to use a half-year convention for personal property or mid-month convention for real property. Under such a convention, all property of a particular type is considered to have been acquired at the midpoint of the acquisition period. One half of a full period's depreciation is allowed in the acquisition period (and also in the final depreciation period if the life of the assets is a whole number of years). United States rules require a mid-quarter convention for per property if more than 40% of the acquisitions for the year are in the final quarter.

title: Depreciation


text:
Talk:6 Music

This needs to be merged with BBC 6 Music. --rbrwr

title: Talk:6 Music