Most digital cameras use autofocus to ensure that, when you take a portrait, your subject is always in focus. This works quite well but it does limit the way you use your camera and is often not what you want, so learning how to use autofocus and focus lock is the key to taking pictures that will mark you as a good photographer.
How Autofocus works
Autofocus works by calculating the distance between what appears to be the subject you want to photograph all the way back to the camera and then setting this as the focus. Often there are a pair of brackets or a circle in the screen or viewfinder to indicate what the camera is focusing on.
Most of the time this works well but you can get pictures out of focus, often because the autofocus got it wrong and set the focus to the background instead of what you wanted. This also happens when you want to shoot a person or object that is not in the centre of the shot.
Belt and braces
To counter this, the first tip is to always take an extra shot or two to ensure that you have a selection of photos to choose from. Without the cost of film, digital photos are cheap so it is good practice to take several pictures both to ensure that you get at least one in focus and also that you can choose the best.
Breathe, hold and let go
Sometimes you only get one chance of a shot and here you must try to make the most of it and give the autofocus a chance to get it right.
First, try to get the subject squarely between the brackets in the viewfinder and steady the camera as best you can or hold it against a wall or other support.
Now breathe and hold that breath while you let the autofocus work and, after a slight pause, gently press the shutter.
This way both you and your camera are at their most stable whilst preparing to shoot and actually taking the photo. This gives the autofocus its best shot at getting the focus right.
Focus lock
Autofocus can work well for pictures where the subject is in the middle of the shot but often that's not the picture you want to take.
If you have time to compose your picture you may want a more artistic and better composed shot with a person (or two) in the left or right third and the rest of the photo taken up with background. Try this with an autofocus camera and the focus point will be the background.
So here is a simple four stage plan to get round this using focus lock:
- Compose the picture in the viewfinder or screen so you see it as you want it to be when finished
- Now swing the camera smoothly so the people you want to shoot are directly in the centre and thus in focus
- Press the shutter half way and you should get an 'OK to shoot' indicator showing that the camera is correctly focussed. With the shutter held half open like this, the focus is locked and whatever else you do you will not change it
- Now slowly move back to the composition you want, keeping the shutter half-pressed and then, when you are ready, press the shutter all the way down
The focus will be correct for the people, even though the brackets are now set to the background. Your picture will show the subject in focus with the background slightly out of focus.
If you've never done this before don't worry if it doesn't work the first time, with some cameras there is a bit of a knack to it so practice a few times and you will get it right.
Autofocus and focus lock are very useful aids to photo taking but to get the most out of them you need to understand how they work and practise using them.
