FOCUS FOR ACTION
Adapt your skills for quick-fire focusing with pinpoint accuracy
Working with focus in the fields of sport and action photography is an almost inverse experience to that found when photographing landscapes. While precision is still key, since this is critical for rendering sharp images, the approach to how it is achieved differs significantly. This is largely due to the native depth of field of the lenses in use, which is far narrower and therefore less forgiving of focusing errors with telephoto optics than when using wide-angle focal lengths. Instead of attempting to get many widely spaced areas in focus, the photographer will often be aiming to capture a small region of densely arranged detail, but with the additional complication of rapid and often erratic movement. In common with genres such as street and documentary imaging, there is a requirement to create as many sharp images as possible in a continually evolving scene. The subject type, camera position and speed of subject movement will define the photographer’s approach – the decision to either pre-set focus or attempt to track the subject using autofocus.
Modern AF systems make use of highly sophisticated algorithms, which are capable of managing the majority of commonly experienced shooting environments. Most of the problems expressed by photographers stem from a misunderstanding of how these systems function, when each mode is best employed and under which conditions complications are likely to arise. An incorrect choice of autofocus mode has the potential to compromise the speed and accuracy of the system, as the camera will be ‘looking’ for a type of subject movement that is not occurring in reality. For example, leaving the camera set to the highest AF sensitivity, so that it rapidly shifts focus to cater for new objects in the frame, will likely result in misfocusing where obstructions are passing in front of the subject. Such a mode is therefore unsuitable for tracking a single player in a football game for example, when shooting at pitch level and not from an elevated position. Any deficit in understanding of how a camera will behave in a variety of scenarios can lead to a mismatch of ‘intent’ between the photographer and the AF system, resulting in shots that fail to fulfil our expectations.