How to focus a camera
camera focus techniques
There are two ways to focus a camera (three if your camera has a touch-screen):
Auto focus
Manual focus using the lens ring
Manual focus using the touch screen
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How auto focus works on a camera
When you half-press the shutter button the camera assesses the scene and decides what needs to be in focus based on:
what’s closest to the camera
what’s highest contrast in the scene
what’s nearest the middle of the frame
If you want to override these decisions but stay on auto focus you’ll need to take control of the auto focus (AF) points. Look up in your manual (or do an online search for your camera make and model) and find out how to change the AF point that the camera uses.
Viewfinder showing central AF point lit up in green indicating this is where the focus has been fixed
Viewfinder showing top AF point lit up in green indicating the photographer has moved the default AF point, or that the camera decided this was the best place to focus
Static vs continuous auto focus
The default setting is for a static auto focus setup. This means that once the camera achieves focus (notified by a beep and/or the AF point flashing green in the viewfinder) the camera will focus at that distance whether or not anything in the frame moves.
If you are shooting wildlife or sports you would use a continuous focus option. Once the camera has “acquired” the main subject then it will follow the subject around the frame holding focus even if the subject moves further away or nearer to the camera. The tricky part is acquiring the subject in the first place and you’ll need to consult your manual for this.
Single vs multi area auto focus
Your camera will have the option to use just one AF point or to take advantage of many. Check your manual to see what your options are and then - importantly - try them out. It may be that your camera’s multi AF option works really well and you don’t need to change anything. Or you may find you prefer the fine control you get working with a single AF point.
Focus-recompose
If you don’t like the extra buttons involved in moving the AF point while you’re taking a shot, you can try the focus-recompose method for achieving sharp focus every time.
Line the camera up so the default AF point is over your subject.
Half press the shutter button and hold it half-pressed.
Keep holding it half-pressed and move the camera to get the composition you want.
Press the shutter button all the way to take the shot.
The camera will hold the focus between steps 2 and 4 as long as you don’t take your finger off the shutter.
Back-button focus
Another way of giving you more flexibility when you are shooting is to move the focus function away from the shutter button. You can assign it to a button on the back of your camera (hence back-button focus) and then use your thumb to focus and your forefinger to fire the shutter.
Touch-screen focussing
New cameras with LCD previews on the back may offer touch-sensitive focussing: you just touch on the image where you want to focus. If your camera has this option it probably has two settings: 1. focus only, or 2. ‘focus and fire the shutter’. It can be annoying if the camera keeps taking a photo when you touch the LCD so you might prefer option 1.
Manual focus
If your subject is not fast-moving you can switch to manual focus for more accurate focussing. Find the button on the lens with an “AF-MF” switch and move it to “MF”. In some Nikon cameras this option is buried in a menu so consult your manual if you can’t find the AF-MF switch. Don’t forget to switch back to AF is that’s what you normally use.
Where to focus?
If the subject has eyes you usually want the eye closes to the camera to be sharply in focus.
Whatever is sharply in focus will draw the viewer’s attention, so you normally want this to be your subject: if you’re taking a photo of a tree, make sure the tree is in focus no matter where in the frame it sits.
Regardless of the photographer’s intention in this shot the grass is the subject or the focal point because it is the part of the image most sharply in focus. The tree becomes part of the background.
Camera focus Troubleshooting
Camera won’t take a shot
Are you too close? Each lens has a 'closest focussing distance’ (CFD) and if you are not far enough away from your subject the camera can’t focus. Check online to find out what your CFD is.
Can the camera find something to focus on? If it is too dark or you have a low contrast scene then the AF will struggle and the camera will refuse to take a shot. Move to manual focus.
Image out of focus
Have you left manual focus on?
Is your camera’s face recognition overriding where you want to focus?
Is the auto focus not accurate enough?
Is your depth of field too narrow? (Focus is only the start of a sharp image: you also need sufficient depth of field so that the whole of your subject is acceptably sharp. To learn how to work with depth of field join my free online photography course below.)
Is it a camera shake problem not a focus one? (You need to know about shutter speed as well: a blurry image might be caused by having a shutter speed that is too slow rather than being a focus issue. Again, all this is covered in my free course.)
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