Step by step Get to grips with AF point selection options
You can manually select a single AF point or let the camera select from all the available points
If all the AF points are active, you’re leaving it up to the camera to determine which part of the picture should be in focus. Typically, it will latch onto the object that’s closest, and this may not correspond with the position of the main subject. For more control, select a single AF point. This works well for stationary objects, but it’s challenging to keep a single point on an erratically moving subject.
Some cameras allow you to expand the AF point so that surrounding ones help out, or to manually choose groups or zones of AF points from the full array. The options differ between cameras, but here’s what’s typically on offer on a multi-point model, illustrated by the Canon EOS 5D Mark III.
A good option for when you’re photographing close-ups and the regular single point would cover too wide an area.
AF point expansion
Neighbouring AF points assist the one selected, increasing the chances of moving subjects remaining in focus.
Centre AF point
The centre is the most sensitive point, so choose it if you find the camera struggles to focus.
A zone of points is manually selected, but the camera chooses which AF points to use within a zone.
Off-centre AF point
You may have to press a button before cycling through the AF points using the control dial.
The camera chooses which AF points to use – but at least you can manually set a single AF point as a starting point.