INTRODUCTION

Close-up and macro underwater photography can to be readily defined and distinguished in relation to the Nikonos range of cameras, where it is necessary to use supplementary close-up lenses for close-up photography of small subjects and extension tubes for macro photography of very small subjects. These definitions, however, break down when applied to a housed land camera with a "macro" lens, as a "macro" lens is capable of covering macro, close-up and standard subjects. So, the boundaries between macro, close-up and standard photography differ from one system to another. As the Nikonos range of cameras is the most widely used underwater, this discussion on close-up and macro photography is principally aimed at users of this camera and the terms close-up and macro are used in relation to the Nikonos.

CLOSE-UP LENSES

Close-up lenses are attached to the front of the camera's primary lens, reducing the minimum subject to lens distance by a half or more. They enable you to get closer to the subject and consequently reduce the amount of water between subject and lens, providing sharper definition. As with extension tubes, the reduced focal distance unfortunately also means a reduced depth of field.

None of the available amphibious cameras are single lens reflex (SLR) and the camera's parallax viewfinder cannot be used when using a close-up lens. To help overcome the difficulty of focusing and composing, close-up lenses are usually supplied with a framing device.These vary from one manufacturer to another but all define the subject area and focal point. Each framer can only be used with a specific lens.

In order to photograph a small subject, all one needs to do is to frame it and press the shutter release. However, unless very close to the surface in clear bright water, you will need to use an artificial light source such as an electronic flashgun or strobe.

Close-up lenses may be removed underwater, although this is not straight forward with some systems. In fact removing the lens underwater is necessary with all close-up lenses prior to use, in order to flood the space between the camera's primary lens and the close-up lens. This removability underwater gives you a choice between close-up and standard shots on the same dive.

Close-up lenses are available for the Sea & Sea Pocket Marine and Motor Marine 35 and the Nikonos range of cameras.

EXTENSION TUBES

Extension tubes are either metal or inject ion-moulded plastic tubes, which fit between the camera body_and the camera's primary lens, extending the distance between the film inside the camera and the front of the lens. Although extension tubes are available for most land cameras, the only tubes available for amphibious cameras are for use with the Nikonos 35 mm and 28 mm lenses.

The extended distance between film and lens created by insertion of an extension tube, means that the focal point is brought very much closer to the lens.

Unfortunately, the reduced focal distance also considerably reduces the depth of field. In addition, since the Nikonos is not a single reflex (SLR) camera, you cannot use the camera's own parallax viewfinder to compose your picture when using extension tubes. To help overcome these problems, all extension tubes are supplied with a framing device. Framing devices vary from one manufacturer to another but all indicate the subject area and focal distance. Each framer can only be used with a specific extension tube or combination of tubes.

In order to photograph a small subject. all one needs to do is to frame it and press the shutter release. However, unless very close to the surface in clear bright water, you will need to use an artificial light source such as an electronic flashgun or strobe.

Extension tubes for use with the Nikonos 35 mm and 28 mm lenses are available in two or three different lengths, often supplied as a set, complete with framing devices. The longer the extension tube, the smaller the subject area covered. Some extension tubes are designed so as to stack one on the other. allowing a greater extension and consequently coverage of an even smaller subject area.

Rather than specifying the length of an extension tube, it is common practice to specify the size of the subject area covered in relation to the size of a single frame of 35 mm film. Thus a typical extension tube which covers a subject area the same size as a single 35 mm, frame is described as a "1 : 1 extension tube". Similarly, an extension tube which covers a subject area twice the size of a single 35 mm frame is described as a "! : 2 extension tube" and an extension tube which covers a subject area three times the size of a single 35 mm frame is described as a "1: 3 extension tube".

Extension tubes should be fitted before diving and should not be removed underwater!

LIGHTING

You will need a source of artificial light in order to take close-up or macro photographs. It is not necessary to use the largest and most powerful flashgun available. In fact you should try and use a flashgun with as small an angle as necessary to cover the subject area.

Before you set off in earnest to take your first underwater close-up or macro photographs, shoot a test roll for each combination of lenses and or extension tubes. For this you will need a test card or some other colourful, waterproof subject such as a Rubic cube or metal tea tray and a roll of slide, not print, film.

Beforehand, note down on a waterproof slate the numbers 1 to 12 and next to each number the intended from f4 to f22 in half stop intervals. Take your test shots underwater at the fixed distance dictated by your framing device and at the predetermined apertures, holding the flashgun to the one side and slightly above and pointing at the centre of the test subject. Repeat this for each combination of lenses or extension tubes you intend to use. Once processed, compare the results with the test card or whatever you used for the test. Note which gives you the closest colour match between film and test subject for each combination of lenses and extension, tubes. Use these apertures as your guide for all future underwater close-up or macro photographs. Remember, however, that light subjects reflect more light and dark sublects absorb more light. So underexpose light subjects (increase f-stop) and overexpose dark subjects (decrease f-stop) by a half to one stop.

The angle of illumination is important and varies with different types of subject. For standard shots of all subjects, except those which are translucent, try to illuminate the subject from above and to one side, just as you would a much larger subject. As you will not see any shadows until your film is processed. try taking the same subject with the flash at two or three slightly different angles. If you use two flashguns, one either side of the subject, you will eliminate shadows and tend to give the resulting image a rather flat appearance.

For a translucent subject, such as a jellyfish or comb jelly, holding the flashgun to one side and slightly behind the subject is a better means of providing illumination, as the subject will appear to light up from within. If you want a dramatic effect. you could try illuminating your subject from behind or below or you could try using coloured filters on your flashgun.

OTHER TECHNIQUES

When taking close-up and macro photographs take care not to disturb your subject unduly with the framing device. Even a light brush with the framer may cause your subject to contract or withdraw. When composing your shot by lining up the framing device with the subject, try to get your eye as close to the top of the camera as possible so that you see approximately the same subject area as the camera lens. You can see the difference this could make merely by holding up two fingers and moving your head around whilst looking between your fingers, but be careful not to try this on the bus home!

Close-up and macro photography using a supplementary close-up lens or an extension tube with a Nikonos is possibly the easiest type of photography to undertake at night, as you don't need to see well enough to focus, as you would with a housed land camera. Provided you have a not too powerful modelling light or small torch (many night active creatures shun bright light) you can easily frame your subject and shoot knowing you are correctly composed and in focus.

SUMMARY

A supplementary close-up lens will extend your photographic possibilities. particularly when underwater visibility is not particularly good. Extension tubes will provide the best means of taking really close macro shots of small subjects or detail of larger subjects. Artificial light is necessary for all close-up and macro photography. Provided you shoot a test roll before you start, every photograph you take should be perfectly exposed, composed and in focus.

Reproduced from in focus 32 (May. 1989)