A number of problems present themselves and first and foremost if finding a spot where they feed in decent numbers and you can get down low and close to where they feed. RSPB reserves often have loads of terns thanks to the provision of tern rafts for them to breed on. In most cases they are a fantastic place to watch the terns but not so good for getting the particular shot I am after. There are also some great coastal locations such as the Farne Islands, where the terns will peck your head. Getting there for me is a two or more day jaunt so again can be problematic with work constraints etc. Fortunately, I live near the wonderful Tring Reservoirs, all four of which terns gather in good numbers. Of the four, Marsworth and Startops are where I have had most luck so far.
The next problem for me is the fact they are white. I often struggle to get the metering right whenever shooting white birds. If I meter well for the body then the surroundings are often dark as is the black area on their heads and around their eyes. It is a classic situation where overly bright light can increase the difficulty, and when those golden hours in the morning and evening provide the best chances.
When the skies are full and the terns are feeding I usually sit and watch for a while. Some spots on the water seem to be favoured by the birds. I am guessing it is partly due to wind direction partly due to light and partly because the shallow areas seem to be where shoals of small fish gather. Once I have located my spot of choice I get down low, up the shutter speed as high as I dare and wait. Often the terns will hover a bit before they dive giving plenty of warning, other times they are belting along then just drop. The latter I usually miss, I am just not fast enough. When they hover I focus intently on them and try and track them as they dive. Again, I need far more practice as I am simply not as adept as I could be.
Sometimes I do manage to get most things right. As ever this is the natural world before us, one in which the creatures we are photographing just do not want to play ball. While I am not yet happy, with plenty of near misses to the shot I picture in my mind, I have managed to get close. Sometimes distance has been the problem, sometimes the birds have not hit the water at the correct angle for my chosen location but most of the time it is me that screws it up. It is a challenge the I really enjoy and one that I am sure will go on for many years. If I ever get to the point where I am really happy with my work there will be little point in carrying on. I will always feel I can do better and that is a good thing as it drives me to get out there with the camera.