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Doug Allan - Freeze Frame

Close-up and macro photography

by Brian Pitkin

Reproduced from in focus 17 (Aug. 1986)

A standard lens such as a 50mm land lens in a housing or the Nikonos 35 mm lens will allow photographs to be taken underwater at a minimum distance setting of about three feet. With a Nikonos 35 mm lens set at f22 this means that anything closer than about 18' to the lens will be out of focus.

It is possible to take sharp, in focus, photographs closer than this using a wide-angle lens. However the resulting image will be distorted, particularly at the edges of the picture.

To obtain near distortion'free images at closer distances than can be achieved with a standard lens, underwater photographers have a choice of two options, both of which involve changing the characteristics of the lens system.

Firstly, the primary lens can be changed for another with a shorter focal length or its focal length may be altered by the addition of an accessory or secondary lens. For the underwater photographer with a housed camera, a macro lens such as a 55 mm macro lens provides a very versatile means of getting closer to a subject without losing the ability to take scenic shots with the same lens. For the owner of an amphibious camera, however, there is no alternative but to use a secondary or 'close'up lens'. Since this secondary lens can be removed underwater if needed, the photographer can still use the primary lens to take scenic shots.

Secondly, the primary lens can be moved further from the film plane by inserting a so'called 'extension tube', which extends the distance between the lens and film plane and thus allows the lens to be brought very much closer to the subject. Unlike close'up lenses, however, extension tubes cannot be removed underwater, at least not without flooding the camera!

Although I have suggested that there are two options available it you wish to get close, these options fullfill different needs. These needs depend on what you wish to photograph.

A standard lens such as the Nikonos 35 mm will cover an area of about 90 times the area of a 35 mm transparency at a distance of about three feet, Obviously, if you fit a close'up lens or extension tube to the primary lens, in order to get closer to your subject, the area you will cover will be considerably less. In fact the addition of a close'up lens to a 35 mm lens will enable you to photograph an area of less than half that of the 35 mm lens without a close'up lens attached. By comparison the addition of an extension tube will limit you to an area of only three times the area of a 35 mm transparency or less, depending on the length of the extension tube.

CLOSE'UP LENSES

There is an almost infinite range of lenses available for housed land cameras, the 55 mm macro lets being the most popular as it allows both close'up and scenic photography. For amphibious cameras, such a Nikonos, there are a smaller number of accessory close'up lenses available which can be fitted onto the 35 mm, 28 mm or 80 mm lenses, and as I have already mentioned these can be removed underwater should you wish to take scenic or non close'up shots.

One of the difficulties of fitting a close'up lens onto the primary lens of a Nikonos is that the camera's parallax viewfinder is totally useless for composing your picture. In addition the depth of field is drastically reduced, so that focusing becomes extremely critical. The problem of composition may be partially solved by the use of a framing device or probes, provided with all close'up lenses. This also overcomes the problem of focusing. The framing device or probes only partially solve the problem of composition because your eye can never be exactly in line with the lens. You do not see exactly what the camera sees as you tend to be looking down over the top of the camera at your framer and the subject. With practice, however, this minor draw back can be taken Into account.

Normally the same close up lens can be used on either a 35 mm, 28 mm or 80 mm lens. The focal distance will remain the sam, only the area covered will differ. A close'up lens on a 35 mm lens will cover a larger area than the same lens on a 80 mm lens and the same lens on a 28 mm lens will cover a larger area than either an 80 mm or 35 mm. Normally framers or probes are provided with your close'up lens for use with two or more different primary lenses.

Your choice of close'up lens will depend on how much you want to spend and your reasons for taking photographs. The Nikonos close'up system is excellent, if somewhat overpriced. The lens is clamped onto the outside of the primary lens and additionally secured in place by a rod inserted in the hot shoe of the camera body_. Since it is normally necessary to flood the space between the close'up lens and the primary lens it is all too easy to lose this small rod, unless you tie it on. The lens comes with three framers for the 35 mm, 28 mm and 80 mm lenses.

The Ocean Optics close'up lens is very similar in specifications to the Nikonos close'up lens, although considerably cheaper and more compact. It is provided with a pair of probes rather than a framer. The lens is clamped onto the outside of the primary lens. The probes screw into the front of the lens mount in one of two positions, depending on whether you fit the lens onto a 35 mm or 28 mm primary lens.

Close'up lenses are also available for the Sea and Sea Motormarine SE 35 mm camera and the Sea and Sea 110 Pocket marine. These are screw on supplementary lenses with a single focusing probe or wand. It is also possible to buy simple, cheap but effective, lenses to screw onto Nikonos lenses, but you will need to shoot a test film to determine the focal distance and make up your own focusing rod to use these.

Whether you choose a close'up lens with a framer or with probes, will depend on personal preference. Although probes are less likely to cause shadow problems and are more versatile, they may be, initially at least, more difficult to use for accurate framing.

EXTENSION TUBES

Extension tubes fit between the camera body_and primary lens. Once fitted, they cannot be removed underwater.

The available tubes for Nikonos cameras reduce the lens'to'subject distance to between 1 7/8 inches and 5 inches, so even in very poor visibility you can still take reasonable photographs. With such a small working distance, of course, the area covered will be very small as compared to the standard lens on its own. Tubes are described by the reproduction ratio that they can achieve. At the upper end, a 1:3 extension tube, will enable you to cover an area 3 times the size of a 35 mm transparency; working up in magnification, a 1:2 extension tube will enable you to take half life-size photographs; a 1:1 will allow you to take life-size photographs; and a 2:1 extension tube will allow you to take photographs at twice life-size. In practice a 2:1 or 1:3 reproduction ratio is achieved by combining 1:2 and 1:1 extension tubes.

As with close'up lenses, there are problems of focusing and framing when using extension tubes. These problems are overcome in the same way, by the use of framers or probes. Depth of field is greatly reduced, so your subjects must be fairly flat if they are to be completely in focus.

Tubes for the Nikonos are made by Oceanic, Ocean Optics and Sea and Sea. The Oceanic and Ocean Optics tubes are made from machined and anodised aluminium, whereas those made by Sea and Sea are made from injection moulded plastic. The Oceanic tubes come with a fixed metal framer. The framer supplied with the Sea and Sea tubes has removable side probes. The Ocean Optics tubes have a pair of probes. The latter are also available in a vertical format version.

Prices vary, the most expensive is not necessarily the best. Aluminium has the advantage of being more robust, I have seen two cameras flooded In succession whilst using the same moulded plastic extension tube with an unnoticed hair line crack.

LIGHTING

Unless you are extremely close to the surface you will need to use artificial light in order to correctly expose your subject and bring out the colour when taking close'up or macro shots. An electronic flashgun provides the easiest solution. It does not need to be a very powerful flashgun, nor does it need to cover a wide-angle. Provided the flashgun will allow you to expose a subject at f16'22 at a distance of one foot, it will be perfectly adequate. If you have a more powerful flashgun, you will probably need to either use a diffuser or, if more than one power is available, use half, quarter or one-eighth power, or move the flashgun further from the subject. Too much light and you will overexpose your subject!

Most flashguns are provided with an arm and tray. Although these limit possibilities when taking non close'up and macro photographs, unless you detach the flashgun from the tray and hand hold it, they can be quite useful when taking close-up or macro shots. Aim to position the flashgun so that it evenly illuminates the area within your framer. Slightly to the left and above the camera is usually fine. Although some macro set ups position the flashgun just above the camera's centre, this may flatten the resulting image by totalling eliminating shadows. Once you are used to your system, try moving the flashgun to one side or behind the subject. Balanced light shots are also possible with close'up. Don't be afraid to experiment, you may be pleasantly surprised with your results.

FILM

If you are taking close'ups or macro photographs you will need a fine grain film to capture the fine detail. Kodachrome 64 and 25 are probably the best choice of transparency films, but Ektachrome 100, Agfachrome 50 and Fujichrome 50 and 100 are very strong contenders.

SUMMARY

Whether you use close'up lenses or extension tubes there can be no easier way of taking successful, underwater photographs. Assuming you have run a test film and

a) know the correct setting for a particular colour subject and

b) preset the focal length of your primary lens, following the directions for using your close up lens or extension tube (either closest distance or infinity), then every picture you take should be In focus and correctly exposed.

All you need worry about is finding subjects and composing your shots!


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