Perhaps the most challenging aspect for bird photographers is capturing pleasing images of birds in flight. However, It can also be the most satisfying when you do get it right!
Photographing Birds in Flight (Part 2 – Focus and ISO)
While I typically do use AV (aperture priority) for most of my bird photography, one can also experiment with shooting BIF in Manual mode, where you can select high shutter speeds which are the prerequisite to freeze motion.
Aim for at least 1/1000th second for birds that move slowly through your viewfinder and 1/4000th second for birds that move more erratically. Also consider changing your distance limiter switch on your lens to the furthest focus range. This will reduce the time that the lens needs to acquire focus as it is searching for the subject in a reduced focal range.
As light changes you also have to bear your ISO settings in mind, unless your camera is set on AUTO-ISO. More artistic flight shots could also be obtained however at lower shutter speeds, whereby the body is sharp and the wings are blurred to depict the motion in a different way. This works very well in flock-species birds for instance such as with a large aggregation of flamingos.
It is also important to consider the AF point selection on your camera. The best setting is to just normally have it on the centre AF point, but some of the expanded zones could also be worth experimenting with, especially for erratic flyers that don’t move in a straight line.
Picking up birds in your viewfinder while they are still quite distant also makes things easier. Controlled bursts of the shutter (as subject moves through the frame) so that AF system has better chance to keep up with subject can be better strategy than just ‘spraying and praying’ for an in-focus shot. When photographing more than one bird flying together, a smaller aperture would also be more relevant. Photographing flying birds is also better on a clear day than an overcast one as this creates far more pleasing backgrounds.
Lastly, it is also just about practice, practice and more practice, especially with regards trickier subjects like swallows, falcons and smaller passerines.
Read Part I of Martin's 'Birds in Flight' post on Gear here.