Housed Camera Systems
- Relatively bulky and heavy
- Usually more expensive
- Allows you to use a variety of SLR cameras, which can also be used above water
- Large selection of lenses available
- Allows through the lens viewing for composing and focusing
- More complicated to operate
- Ideal for photographing fish or shy subjects
An underwater camera housing is merely a plastic or aluminum water-tight box that encases a single lens reflex (SLR) camera. This enables you to bring many varieties of cameras underwater for both wide angle and close-up photography. It’s possible that your favorite camera may be adapted for use underwater if an appropriate housing is made for that particular one. If you already possess such a camera and several lenses (such as a macro lens and 20 mm), then the expense of purchasing a camera system for underwater use is avoided. Of course, the cost of the housing must be considered, which can be considerable.
Housings generally permit you to operate most of the camera functions, such as changing apertures, focusing, tripping the shutter and changing the zoom setting (for zoom lenses). With more advanced cameras you may also be able to change exposure modes (shutter priority, aperture priority, program and manual), strobe exposure control (manual vs. TTL) and focusing (manual vs. autofocus). This of course means that you should have a thorough understanding of how your camera functions before you consider taking it into the water. Perfectly good photographs may be made with simple manual camera systems. More and more underwater photographers, however, are converting to the use of autoexposure and autofocus cameras.
Manual cameras require the use of gear rings attached to the lens that engage with a set of gears on the housing for controlling lens aperture. This enables the photographer to turn a knob, which results in a corresponding shift in the aperture setting. Turning of the lens barrel for focusing is accomplished with an attachment on the lens that engages with the housing. With automatic control of focus and exposure, these lens attachments are unnecessary since the changes are made electronically. You may wish to still use a focus ring however in order to retain the ability to shift to manual focus while underwater.
A component known as a port is attached to the front of the housing. An o-ring seals the gap between the port and the housing. Ports come in two varieties – flat and domed (curved) front. Flat ports are generally used for close-up (macro) lenses. They do not correct for refraction, with the result that a 50 mm lens effectively has a longer focal length underwater. Dome ports are typically used for wide angle lenses (28 mm and less, including wide angle zooms such as 20 – 35 mm) and do correct for refraction, so a 20 mm lens retains the same angle of coverage as it would have above water. Without a dome port, a wide angle lens would suffer severe distortion. The viewing surface of most ports is usually made of acrylic plastic. Acrylic is easy to scratch so care must be taken when using the housing. Glass ports are quite a bit more expensive but less prone to being scratched.
Ikelite Underwater Systems makes a variety of clear polycarbonate (lexan) housings for SLR cameras. These housings are relatively inexpensive but nevertheless can yield excellent results. The clear lexan can actually be an advantage in that water leaks are readily apparent (but not a happy situation to observe!). Corrosion is not a problem as it can be for aluminum housings. Plastic housings are not as rugged as their aluminum counterparts, however. The gear connection between the housing and lens also tends to be less rigid. Aluminum housings are far more expensive. Newer versions are quite compact and surround the SLR camera very closely, resulting in a nice slim package. Manufacturers of aluminum housings include Subal, Nexus and Aquatica (now part of Nikon). The most popular cameras for use in housings are the various styles of Nikon, with Canon EOS style cameras next in line. The Canon F-1 (an older manual camera) and the F-series Nikons (F3, F4 and top of the line F5) have removable viewfinders that permit the addition of large viewing area viewfinders. Other cameras have small viewfinders that make composing and focusing underwater difficult since your mask and the housing prevent putting your eye directly at the viewfinder.
The big advantage of housed systems over the Nikonos is the ability to view the scene directly through the camera. Composing the image can thus be more precise compared to the Nikonos, in which an accessory viewfinder is used. Focusing is also done directly through the camera. When using a macro lens, it’s generally best to set the desired image magnification (such as 1:2 or 1:3) and then move the housing carefully back and forth while looking through the viewfinder until the desired focus point is reached. Macro lenses in the 50 mm and 100 mm range are generally used. At most, subject distances will be 3 feet, but usually less than 2 feet for best results. Longer focal length macro lenses have an increased working distance, an advantage when photographing shy fish. Most macro lenses can focus down to a 1:2 image ratio (half life size). An extension tube can increase that to 1:1 (life size on the film). Macro lenses, particularly 100 mm or when used with an extension tube, require longer ports in order to accommodate lens extension. A housing eliminates the need to employ macro framers that are often used for the Nikonos. Framers have a tendency to get in the way, prevent many situations from being photographed, and can scare the subject away (or even damage it in the case of delicate invertebrates).
For wide angle lenses with a dome port you are actually focusing on a virtual image that lies within a foot or so from the lens (we’ll discuss what a virtual image is more completely later on). Depth of field generally covers the focus point if the lens is set just under 1 foot. Some lenses may require an accessory diopter in order to focus this close. With a wide angle lens, the advantage of SLR viewing and focusing becomes more apparent the closer you get to a photo subject. Precise composing of subjects with a wide angle Nikonos set-up becomes difficult (if not impossible) when you get within a distance of a foot or so.
With the appropriate connector cord, most strobe units can be connected to any housing. With a TTL strobe and TTL-capable camera, through-the-lens exposure control is possible. Housings generally have a connection between the external strobe cord connector on the housing and the hot shoe of the camera. TTL exposure control is generally most effective in situations where the strobe provides most of the illumination on the subject, such as with close-up photography. It’s less useful for wide angle and other situations where ambient light plays a role in lighting the subject area.
Nikonos Systems
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Relatively compact and easier to travel with
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Simpler to operate compared to a housing
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Requires an accessory viewfinder for composing the photo
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Limited selection of lenses available
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Can be less expensive to purchase a functional system
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15 mm and 20 mm lenses not suitable for use above water
Ask any old-time underwater photographer what system they started with, and more than likely the response will be "Nikonos". For ease of use and learning, the Nikonos system is hard to beat. The Nikonos V, the latest in the series, has been around for many years and has proven to be a reliable and effective performer. The original Nikonos I dates back to the early 1960’s. Thousands of photographers have honed their underwater photo skills with the Nikonos system, with many sticking with it, and with others shifting to housed systems.
The early versions of the Nikonos (numbers I, II and II) were entirely manual cameras. They do not incorporate any electronics (such as a light meter or autoexposure), and thus require the use of an accessory light meter for determining proper exposure. A dial on the top is used to change shutter speeds – no other control is present on the camera body. Although limited in their capabilities, these early versions are nevertheless quite capable of producing excellent photography in the right hands. They also are extremely rugged and are more likely to resume function after a flood (which can spell permanent doom for a complex electronic camera).
The Nikonos V has added some electronic features and served thousands of photographers with a design that has stayed constant since the early 1980’s. By modern camera standards, it certainly is a primitive design. The Nikonos V incorporates a lower center and bottom weighted lightmeter for measuring ambient light levels and a separate sensor for determining TTL strobe exposures. Rather than indicating the appropriate lens aperture, the LED read-out visible in the viewfinder indicates the proper shutter speed setting for the lighting situation and current lens aperture. Available shutter speeds range from 1/30 to 1 second, which are controlled by a dial on the right side of the camera. A manual setting (M90, or 1/90 second) can be used without a battery, but an accessory lightmeter is then required to determine exposure. The automatic setting (A on the dial) is used for aperture priority exposure control (set the lens aperture and the camera determines the appropriate shutter speed). Without a strobe, the A setting can be useful for wide angle situations. Make sure the lens aperture is sufficiently open to have a shutter speed no slower than about 1/30 to 1/60 second. When using a TTL strobe for through-the-lens exposure control, the shutter speed dial is usually set to "A" and the aperture is set to the appropriate f/stop (more on this later). Shutter speeds for manual strobes should be set at M90 or slower. Film speed (ASA/ISO) is set with a dial on the left side of the camera. This dial can also be used when bracketing TTL exposures. Connection to the strobe is via a cord adapter threaded into a port at the base of the camera.
Since the Nikonos is not an SLR camera, viewing of photo subjects is made through a viewfinder and not through the lens that produces the image. Although a viewfinder is built in to the top of the camera, it is not particularly useful. In most cases an accessory viewfinder, attached to the top on the hot shoe, is more effective. Nikon makes a nice viewfinder, as does Ikelite, which is quite a bit less expensive. The major limitation of viewfinders is that they do not necessarily see the same image as would be projected on the film. This problem is known as parallax. If the lens and viewfinder are pointing at the same angle, the viewfinder will "see" an area that is somewhat higher than what the camera is "seeing". If you make an image without compensating for this, most of the subject may actually be cut off in the photo. The closer you get to the photo subject, the more pronounced is the effect. An adjustment is necessary, either by moving the camera angle up, or by rotating the viewfinder down (if it has this feature). At close working distances (1 or 2 feet) with wide angle lenses such as the 15 mm, it may be easier to forget about the viewfinder and just point the center of the lens directly at the subject. This amounts to guesswork, and you may not get exactly what you hoped for. Bracketing camera position is one way to increase the chances of creating that perfect composition.
Another consequence of using a viewfinder system is that focusing is not done directly through the camera as in an SLR. When shooting wide angle images, the focus distance must be estimated, and then set on the lens. A dial on the lens is used for setting the appropriate distance. For this reason, skill at estimating distance must be developed. With extreme wide angle lenses such as the 15 mm, the wide depth of field usually compensates for errors in distance estimation, particularly at small apertures. The 35 mm and 28 mm lenses are not quite so forgiving. Due to the effect that refraction has on light, objects that appear 3 feet away are actually 4 feet distant. The camera sees distance the same way as your eye, however, so the setting on the lens should also be 3 feet. Don’t plan on bringing a yardstick underwater for distance measurements! What measures 3 feet away will actually appear closer, and setting the lens to 3 feet would place the focus point behind the subject.
Close-up photography is also done without directly viewing through the camera. Both the 35 mm and 28 mm lenses can be converted to close-up use through the use of extension tubes. Generally there are three extension tubes for each lens, with the longest providing the most magnification (1:1, or life size on the film). The shortest tube provides a 1:3 ratio (1/3 life size), and the intermediate tube provides a 1:2 ratio (half life size). Typically the distance on the lens is set to closest focus, and the aperture is closed down to f/16 or f/22 for maximum depth of field. How do you manage to compose an image without looking through the camera? Each tube has its associated framer, an extension from the front of the lens that delineates the image area and point of focus. The framer is carefully placed surrounding the subject. Depth of field is very limited with close-up photography, particularly at 1:1, so framer placement is critical. The correct framer must be used for each lens and extension tube combination, or the point of focus will be off. Additional types of lens attachments are available for close-up photography. Regardless of the equipment used, close-up photography almost always requires the use of a strobe (or pair of strobes) to light the subject.
Nikon makes five lenses for use with the Nikonos system: 15 mm, 20 mm, 28 mm, 35 mm and 80 mm. Angle of coverage and closest focus distance for each is listed below. The 80 mm lens is basically useless underwater, and is more suited for above water situations in which exposure to water is likely (such as surfing or rafting). The 35 mm lens is not corrected for underwater use and has an effective focal length more like 50 mm (due to refraction). It has limited use underwater as a wide angle lens due to the short depth of field, which requires fairly precise estimation of distance. The most useful reason to have this lens is with extension tubes for close-up photography. It can also be used above water as a wide angle lens. The 28 mm lens is more capable underwater since it has a greater depth of field at a given distance and closer minimum focus distance. Since this lens is not corrected for refraction, it actually is equivalent to a 35 mm lens underwater, but can also be used above water. It’s not a bad starter lens for an inexpensive wide angle set-up for the beginner. With the appropriate extension tubes and framers, the 28 mm lens can also be used for close-up photography. With the 20 mm lens you enter the realm of true wide angle photography underwater. Its range of depth of field is more forgiving than the 28 mm and 35 mm, and it is corrected for refraction, thus retaining its full wide angle capability. The ultimate for wide angle use with a Nikonos is the 15 mm lens. Although quite expensive, it’s worth every penny for its sharpness, depth of field, and ability to get right on top of the subject. Precise image composition is difficult with this lens due to parallax. You also must take care to get as close as possible to the subject, which can appear quite small in the image if too small or far away. Both the 20 mm and 15 mm Nikonos lenses can only be used underwater.
80 mm: 22.7 degree image angle, 3.3 feet closest focus distance
35 mm: 43.5 degree image angle, 2.7 feet closest focus distance
28 mm: 59.0 degree image angle, 2.0 feet closest focus distance
20 mm: 78.0 degree image angle, 1.3 feet closest focus distance
15 mm: 94.0 degree image angle, 1.0 foot closest focus distance
As with housings, o-rings must be carefully maintained. User serviceable o-rings on the Nikonos V include the back door, lens, battery cap and strobe connection. At the end of each day of photography, you should check and clean these o-rings. A number of internal o-rings (shutter release, door latch, shutter speed dial and ISO dial) are not easily serviced by the use. It’s generally recommended that these o-rings be replaced once a year by a qualified underwater photo service technician. A sticky shutter release or door latch that’s hard to turn are indications that the o-rings require attention.
The choice of using a housed
system vs. Nikonos is an individual decision. What’s perfect for one person or
situation may be totally wrong in another case. Until a few years ago,
before the advent of digital cameras for underwater use, most beginners tended to start with a
Nikonos set-up (or a similar viewfinder system such as the Moto-marine). Close-up
photography, in particular, is relatively easy to learn and somewhat inexpensive for a
Nikonos. Many underwater photographers have abandoned film though and the
Nikonos is fading from view. Professional photographers and serious
amateurs have always favored housed camera
systems for the degree of control they offer. An exception in the Nikonos with 15 mm lens,
which finds its way into many professional camera bags. With an understanding of its
limitations, the Nikonos system is certainly capable of producing excellent photographs in
the right hands. Most professional and serious amateur photographers understand the
characteristics and limitations of both housed and Nikonos systems and may use both depending
on the situation.
Of course, if you intend to shoot digitally
the decision is set with a housed camera system - don't count on Nikon producing
a digital Nikonos.
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