Sharing know-how about UK gardening

Unfortunately, a camera's exposure meter doesn't always calculate exposure correctly, so a dark area behind a fish means that the camera will automatically overexpose the image, creating a photo that looks smoky or washed out.

Fortunately you can use a special grey card (from photographers' suppliers) to set up the exposure correctly beforehand. But remember, if you use an 18% gray (mid gray) card to calibrate the camera exposure, check that the light falling on the card is the same quality as the light falling on the area of the pond you're going to photograph.

If the colours are still smoky, and you're using print film, it's likely that the automatic settings at the print processing lab are causing the problem. So go back with the negatives and prints, explain what's wrong with the colours, and ask for reprints.

If you haven't got a grey card, you could bracket the exposures (i.e. repeat the shot with adjacent exposure settings), but duplicating the image is often impossible because Koi move quite quickly. Also, you can guarantee that the best composition of the set of bracketed shots will be the one that is incorrectly exposed. This is the same law that ensures buttered toast always falls face down on the floor. Instead of bracketing, you could use the exposure guide supplied with the film (really!) to decide how much the camera's light meter is being fooled.

An additional problem is the polarising filter. I've always had to fit this to remove surface reflections when photographing Koi. The filter darkens the image seen through the viewfinder, and recorded by the film, so I have had to increase exposure by as much as two and a half stops. This means either setting the camera to a slower shutter speed (increasing the posiblity of camera shake), or increasing the lens aperture (which narrows the depth of field, so reducing what is in focus) or adjusting both of these settings.

In practice

I use 100 ISO for digital or transparency film for fine grain high quality colour photos for publishing. A day with bright but hazy sunlight is ideal for photographing Koi. Before I put a polarising filter on the lens, one exposure option is f8 at 1/125sec. With care these settings produce good sharp photos without using a tripod. After I put the polarising filter on the lens, the exposure options can be between f4 and f2.8 at 1/125sec, f5.6 and f4 at 1/60sec, or f8 and f5.6 at 1/30sec. I instantly reach for the 50mm (standard lens) because this lens has a wide range of apertures to choose from. I set the lens aperture between f4 and f2.8 to give me the fast 1/125 sec shutter speed. None of my other lenses have apertures that open wide enough, so only the 50mm will do the job.

If you haven't got a 50mm lens and the photo is not for publication then you could use high speed film to boost the shutter speed, but expect grainy images and less colour saturation. You could try photographing on a sunny day, but watch out for contrast problems. I've had to photograph Koi on sunny days and been successful - it's just a matter of making the best of it and taking lots of shots in order to get one or two good ones.