Story and photography by Ethan Meleg
In bird photography, we want to have our cameras set up in a way that ensures the greatest chance of capturing sharp photos most of the time. For this reason, almost every bird photographer shoots in a continuous auto focus mode (e.g. AI Servo for Canon; AF-C for Nikon) because birds move and auto focus responds to those movements. The downside of continuous AF if it’s always engaged is that focus can accidentally jump off the bird and onto something else (such as a stick in the background), resulting in an out-of-focus bird. Also, if continuous AF is always running, you can’t easily focus on the bird and then recompose so it’s off-centre in the image without a good chance that focus will shift to something other than the bird. Although there are a variety of ways to address each of these issues, the best (fastest, most reliable) way I’ve found to take advantage of the benefits of continuous auto focus, but still have control over it when needed is to set the camera for back-button auto focus. This way I engage AF with my thumb independent of the shutter button, giving much greater control over when I auto focus and reducing the chance of accidental focus ‘jumps’ off the bird.
To continue reading Ethan’s column on when and when not to use back-button focus for birds and to read more of this issue please pick up the Summer/Fall 2016 (#38) issue of OPC. Or to never miss an issue please SUBSCRIBE today!