Which autofocus mode should I be using?

Autofocus systems have two independent settings and camera menus present them as though they were one. Separating them in your head is the whole skill.

Step by step

1. Set the focus mode: single or continuous.Single — AF-S or One Shot — focuses once when you half-press and locks. Continuous — AF-C or AI Servo — keeps adjusting for as long as you hold. Automatic switching between them exists and is unreliable enough that most people are better off choosing.
2. Use single for anything still.Landscapes, still life, architecture, a posed portrait, anything on a tripod. The lock is a genuine advantage: focus, then recompose slightly, and the camera does not change its mind.
3. Use continuous for anything that moves at all.Children, pets, sport, events, someone walking towards you, and — unexpectedly — a portrait where the subject is breathing and swaying. At shallow apertures, human sway is enough to lose focus between the lock and the shutter.
4. Now choose the area separately.This is the setting that decides where in the frame the camera looks. A single small point gives you complete control. A small zone follows a subject with a little tolerance. Wide or automatic area lets the camera pick, which usually means the nearest high-contrast thing.
5. Use a single point where precision matters.Place it on the eye, on the label, on the plane you want sharp. It is slower to move around the frame and it never focuses on the wrong thing.
6. Use subject and eye detection where it exists.Modern cameras detect people, animals, birds and vehicles and hold focus on the eye. It is genuinely transformative for portraits and pets. Turn on the specific subject type — a camera set to detect vehicles will ignore a dog.
7. Stop recomposing after locking at wide apertures.Focus, then swinging the camera to reframe, moves the focused plane by more than the depth of field at f/1.8. Move the focus point instead, or use a joystick or touch screen to place it.
8. Consider back-button focus.Assign focusing to a rear button rather than the shutter. The shutter then only takes pictures. You focus when you choose, hold for continuous, release to lock — and you stop refocusing accidentally every time you shoot. It takes a week to get used to and most people never go back.
9. Match the drive mode to it.Continuous focus with single-shot drive gives one frame; with continuous drive it refocuses between frames. For anything moving, continuous focus plus a burst is the combination that produces sharp frames.

Tips

• Half the shots people describe as soft are the camera focusing correctly on the wrong thing. Watch which point actually confirms.
• In poor light, autofocus needs contrast. Aim at a defined edge — a collar, a doorframe, the line of a jaw — rather than a flat surface.
• Eye detection tracks the near eye by default on most cameras, which is what you want for a portrait.

Common mistakes

• Leaving the camera on wide-area automatic focus — It selects the nearest high-contrast object, which in a portrait is usually a shoulder or a hand, and in a landscape a branch in the foreground. It is the default and it is the single most common cause of missed focus.
• Using single-shot focus for a portrait at f/1.8 — A standing person sways several centimetres, which is more than the depth of field. Continuous focus with eye detection keeps up; a locked focus does not.

If it doesn't work

Questions people ask