Master your camera’s autofocus: which AF points to use and when to use them
How to choose the best AF point
While for most of us, nine selectable AF points are more than enough, top-end professional cameras, like the Canon EOS-1D X, can have an incredible 61 to choose from. You can even choose multiple AF points in small groups.
Whichever camera you’ve got, knowing which AF point to select can, understandably, be a challenge.
Often it seems easiest is to stick with the central AF point, position it over the object you want to focus on, then lightly press the shutter button to achieve AF.
You can lock the AF setting by holding the shutter button, recompose the shot, then fully press the shutter to take the shot. This often works, but it’s easy to come unstuck.
The main problem with only using the central AF point is that a light reading is also taken, and the exposure value locked, at the same time. If, for example, you focus on an object that’s in shadow, then recompose to include brighter areas, your image will be over-exposed.
Get the point
One answer is to press the AE Lock button after recomposing the image, thereby taking a new light reading, while still holding the shutter button to keep autofocus locked.
But it’s usually easier to pick the AF point that’s closest to the point you want to focus on,
so any subsequent camera movement will be minimal.
Selecting the most appropriate AF point not only ensures more accurate light metering, but focusing as well, because there’s less camera movement after AF has been locked. Plus, AF point placement is based on the rule of thirds, aiding photo composition.
PAGE 1: What your camera’s autofocus points can do for you
PAGE 2: Making the most of your range of AF points
PAGE 3: When to use your different AF points
PAGE 4: How to choose the best AF point
PAGE 5: How to fool your autofocus – and why you should do it
How to fine tune image sharpness using live view
Banish blurry photos: how to keep foreground interest sharp
9 situations when autofocus will fail you
on Thursday, February 7th, 2013 at 4:42 pm under Photography Tips.
Tags: camera tips, How to focus