BACK- BUTTON FOCUSING
As you’ll see later in the guide when we cover AE- Lock, you can set the camera to focus and meter independently, which is useful in particular shooting situations. Some cameras have an AF- L ( AF- Lock) or AF- On button on the rear for this purpose ( hence the term back- button focusing), while with others, you can set a customisable function button to do this for you. You can use the AF- L/ AF- On button rather than the shutter button with both methods ( A and B) described on the right. If you prefer, you can use the AE- Lock button to lock the exposure, then use the shutter button to lock focus.