Composing – The Quick Way
This article is based on Canon camera’s.
In many areas of photography you need to act quick to get “the shot”, therefore we can’t be wasting any time deciding which of the 45 focus points to choose from (this varies from camera to camera). Instead you only need to use the centre focus point.
If I do that, then how am I going to get a composition? Easy, relocate your focus button from your trigger to another button. This is called back-button AF. I usually use the zoom in button or exposure lock button. Then focus, recompose, shoot. In newer Canon models, they have a dedicated button to auto focus separately from the trigger, called AF-On.
Why is this better? You can focus with your right thumb using the back-button AF, and still have your index finger ready for that “once in a lifetime” shot. It is much quicker to use the back-button AF because you can manually recompose faster than choosing a focus point ahead of time. Along with that – it’s a pain using the toggle or scroll wheel to rotate through all of your focus points.
Why do I use back-button AF and centre focus point? Ok, I’ve already mentioned that I find it faster… however the biggest reason is that it’s a pain in the butt to have the camera always trying to focus as you are holding the trigger button half-way down. Right when you are about to take your shot, the camera could unexpectedly attempt to re-focus and you may miss “the shot”.
Why wouldn’t I use the back-button AF? I hardly ever take it off my centre focus point… however if you are doing extremely fine photography you may not want to. Technically, by focusing and then moving your camera to recompose – you are changing the distance to the sensor, which may have some very minor effects on the focus.
How do I change the back-button AF? Find the custom function for your camera and change that setting (refer to custom functions below).