One of the most important aspects of photography is focusing. It allows us to guide the viewer’s eye around the frame, and include and exclude certain pictorial elements. When working with moving subjects focusing can also be one of the trickiest elements to master. Even with modern cameras boasting some of the fastest and most accurate AF systems ever, understanding and knowing how to get the best out of them is an essential skill for the serious wildlife photographer.
Even the most skittish of subjects have to pause for breath occasionally. Whether balancing on a branch or surveying a scene, this behaviour provides us with small windows of opportunity to frame up and make choices about our focus selection. For the most part, you’ll want to be using single-point autofocus in continuous focus mode. Canon calls this mode AI Servo, while Nikon refers to it as AF-C. This allows you to select an AF point, half-press the shutter button and continually focus and refocus on your subject to ensure a sharp shot.
The reason continuous focus mode is important, even with static subjects, is because the smallest of movements, whether yours or your subject’s, can make a big difference to sharpness. Choosing your AF point will come down to compositional preferences, but one thing I often find useful is to deactivate some of my AF points, reducing the number and only working with the cross-type sensors for the most accurate focus acquisition.
When subjects are moving it gets a whole lot harder to keep them in focus, but with practice and persistence you can master the skills to locking on faster.
Firstly, you’ll need to know your camera and its modes, especially if you want to work in a different autofocus mode for moving subjects. I often still work with the camera set to single-point AF in continuous mode for moving subjects, simply selecting the central AF point before I follow the subject’s movement. I do this because the central point has the best consistency and accuracy within the frame. Using a single point, however, means you need to track precisely to ensure your AF point is over your desired area of focus.
For most moving subjects this method of focusing is very efficient when you’re proficient at it, but for certain situations you may want to explore some alternatives.
One of the first alternative modes to look at for moving subjects is group AF. Working with a selected number of AF points (often five), it uses all of them to gain focus on a subject, giving you a wider area to track with for a greater amount of assistance when gaining focus.
Modern DSLRs’ tracking modes have come a long way. 3D tracking autofocus will track a defined subject across a frame, using all of the AF points to keep the original subject constantly in focus. Starting from a defined AF point, once locked on, the camera will automatically track and move the focus point according to the subject’s movement. This is the perfect mode if you’re working with birds in flight or a cheetah sprinting along the plains.
As a final advancement to your focusing techniques, think about switching to rear button focus. Used by professionals, rear button focus gives you the ultimate in control. This mode disables the AF from the shutter button, assigning it to a rear button, often a dedicated AF-ON or the AE-L Lock button. When in use, to focus you’ll have to hold down the newly assigned button to focus, however you can now additionally press the shutter without initiating the AF, meaning you have greater control of when your camera should and shouldn’t focus. It will feel odd the first few times you try it, but persevere as it’ll soon become second nature as well as an excellent skill to have in your photographic arsenal.
Tom Mason is one of the UK’s most exciting young wildlife photographers and conservationists. He leads workshops and seminars and writes a monthly blog for the RSPB. See more of his work here.