Fish are one of the hardest subjects in photography. It doesn't matter if you're diving, or on the other side of a glass tank. Their natural habitat introduces a variety of challenges.

I was recently approached by the West Lothian Aquarist Society, who wanted a basic guide to improving their own fish photographs. The notes are reproduced below for reference.

They include a selection of images which highlight some of the problems, and some things which can be done to overcome them. There are limits to what is achievable, both due to limitations in camera technology, and environmental conditions, but the notes are written with the casual snapper in mind. They relate to taking photographs in aquariums, as well as in the home.


 

Dealing with reflections

 This happens when you have a strong light source coming from directly behind the camera.

1. Turn off background lights if possible.

2. Turn off built-in camera flash. Flash from the camera will bounce right back at the camera.

3. Get the camera as close to the glass as you can (rest the lens against the glass if you can, without damage).

4. Use a lens hood if available. Alternatively, use a dark piece of fabric or clothing to block the light hitting the glass.

5. Try to introduce stronger light from the sides or top of the tank if you can.



Dealing with fringing
 

Fringing is caused by light splitting into its constituent colours when it passes from one material into another. In this case, from air to water, to glass, to air, to the lens.

1. If possible, use a narrow tank with thin glass. Thicker glass increases refraction, causing more fringing.

2. Keep the camera parallel to the glass. Shooting diagonally through the tank will, effectively, increase the thickness of the glass.

3. Remove any protective filters from your lens. Every piece of glass in front of your lens will increase refraction and reduce sharpness, so if you can cut down on the numbers, do so.



Dealing with motion blur without getting flash spots
 

In this shot, low light has led to a slow shutter speed, which has caused motion blur as the fish swims through the shot. Flash from the camera has lit up the scratches in the glass, and caused bright white spots as it reflects off the scales.

Motion blur can be reduced by doing the following:

1. Increase the ISO (camera's light sensitivity). This will cause a bit of noise or grain in your shots, but will reduce the shutter speeds. Short speeds are better for retaining sharp detail (1/60 - 1/ 500 of a second), the faster the better.

2. Move as close as you can, and with as wide a lens as possible (ie. zoom out. Wide angle lenses typically allow more light into the camera than long zooms, and don't exaggerate movement to the same extent.

3. Follow fish by moving the camera with it, keeping parallel to the tank. This is called panning. It slows the movement of the fish, relative to the camera, reducing blur. If your compact camera has a glass window (viewfinder), use this, as it will let you see and follow the fish while the picture is taken. Keep following it until the shutter has closed (usually after a second click). Panning is easier from a distance with a zoom lens, so there's a balance to be struck with point #2.

4. Introduce extra light into the scene, from the sides or above. This can be with flashguns, or from very powerful lamps or torches (million candlepower torches work well, and can be bought for under ten pounds). Flashguns are expensive, but give the best results. If the light looks very harsh, you can diffuse it by shining  it through  a sheet of paper or white perspex.



Focus and impact
 

This photograph is well lit, but fails because of the extraneous background elements, and the fish not being in focus. This is because the camera has tried to focus on the closest object with the most contrast. In this example, the bubbles from the filter (seen in the background) are in focus, but not the fish.

1. Use clean water. Floating particles can confuse auto-focus systems and cause bright spots in photos.

2. Turn off any filters or oxygenators for the duration of the photography. The natural movement of the fish will create bubbles that make photographs look  dynamic, but too many makes a shot look messy.

3. For really graphic shots, remove decorations from the tank. You can also use a piece of card or a plastic tray as a simplified background. This also means that the auto-focus has nothing else to look for but the fish.

4. Use your half-press to pre-focus, don't just stab at the shutter button. This prevents delays when you press the shutter button. Aim to push the button when the fish is near the centre of it's tank, as the edges make distracting lines. Fish look really interesting when in the middle of a turn, so look for these moments.

5. If you have a "sports/ action" mode, use it. This usually comes with continuous (or servo) focus, making it easier to get the shot. If not, use the half-press focus lock, and hold it in place until the fish swims back into focus.

6. Use a wide-angle (again). These keep more of the picture in focus.

Finally, take LOTS of photos. Digital makes this a cost-free matter. Shooting moving subjects is always a hit-or-miss affair, and you won't get a "keeper" with every push of the button. However, use of these tips can get you a better success rate.