The shutter release button has a two-stage action. First pressure on the button activates the metering system and autofocus and pressing it the rest of the way takes the picture. This is standard on all digital cameras – the first half-press gives the camera time to focus. Keeping the button half-pressed keeps the focus locked, though not the exposure – this will continue to adapt as you change the framing of the picture. Nikon DSLRs are unusual in this respect because most other cameras lock the exposure too.
Half-pressing the shutter button to lock the focus is a quick and simple way of dealing with off-centre subjects – it’s a lot quicker than manually shifting the focus point.
- First, position your subject in the centre of the frame.
- Half-press the shutter button to focus on your subject – and keep it half-pressed to keep the focus locked.
- Reframe the shot how you want it.
- Press the shutter button the rest of the way to take the picture.
This only works if you’re using single-shot autofocus mode, by the way. If you’re using Auto Area AF, the D7200 will choose the autofocus point itself, automatically.