Yes, the UK can be a challenging environment for underwater photography. But that does not mean you should leave your camera behind on UK dives! With a bit of planning and a few handy techniques, you will find there are plenty of outstanding photo ops off UK shores. Last weekend I had the pleasure of diving with seals off Lundy Island. Seals have to be one of my favourite UK marine mammals and, with a little bit of luck, are excellent subjects for a photographer.
Low light levels:The main issue facing divers in the UK is the lack of light. Even on a bright sunny day, you don’t have to dive deep before the ambient light levels drop away. Cameras need much more light than our eyes to focus and many compact cameras will try to compensate for low ambient light levels by automatically boosting the ISO, which can result in grainy, low quality images.
The solution? Before you even get in the water turn your camera to a mode that allows you to control the ISO (P programme mode is perfect). On a lovely sunny day an ISO setting of 100 or 200 is ideal. If it is a bit more overcast, try 400. Try not to go over 800 if you can avoid it unless you have a camera that performs well at high ISOs (e.g. Olympus TG model). If you cannot control the ISO, try using the cloudy day setting.
Once you are in the water, stay shallow! Lundy’s seals are frequently found close to shore and often no deeper than 10m. Stay in the shallows and wait for the subjects to come to you. It’s no good chasing seals about or venturing much deeper. Seals are inherently curious and in my experience, there is always at least one brave fellow that wants to investigate these strange looking divers in the water.
Backscatter: Backscatter is the term used to describe the suspended particles in the water column. Light hits these particles and bounces back into the camera. It is then recorded on your picture as a white blob. This is perhaps the number 1 issue for anyone using a strobe or the internal camera flash. Even in good viz, you will find there is some backscatter. In bad viz, your image can look like it is snowing!
The solution? Get close! This is the number 1 rule of underwater photography! The closer you are, the less water there is between you and the subject. Getting close will give you better colours but it also means there are fewer particles to illuminate. If you are using the internal flash, remember this will only travel about 50cm (max) so you really have to be close to your subject for it to be lit.
If you are using an external strobe, angle the strobe outward, away from the subject. If you imagine the light leaving the strobe forming a cone shape, then you want to try to use the side of the cone to light your subject. This softer light is less likely to illuminate the particles in the water but is usually still strong enough to hit your subject.