Focusing is such an important part of photography that camera manufacturers have built in a lot of fancy features to help you along.
One-shot automatic focus is what most people think of when they think ‘autofocus.’ In this mode, when you press the shutter button half way, the camera attempts to focus on the subject your camera is pointed at. When it finds focus, it ‘locks’ the focus until you either take the photo, or you release the shutter button and half press it again. This mode is great for most subjects that don’t move a lot.
Continuous autofocus (also known as ‘continuous Servo’ or just ‘Servo’ focusing) is a mode you find on many advanced cameras. Instead of “locking” the focus (like one-shot autofocus), it continuously tries to keep your subject in focus. This mode is best when you are taking photos of quick-moving subjects that come closer and move away from you a lot.
Canon calls it AI focus, Nikon and Sony call it AF-A mode, but it works the same way: Intelligent Focus is the half-way house between the two previous modes. For subjects that don’t move, the camera uses one-shot autofocus, but if the camera detects movement it switches automatically to continuous autofocus instead and tracks the subject. Generally, the AI Focus mode on most cameras isn’t quite good enough to rely on all of the time, so if you know what you want, it’s best to select one-shot or continuous autofocus yourself.
Manual focus is what it says on the tin: the camera leaves the focusing up to you. On most cameras, when you are focusing manually it will tell you when it thinks your subject is in focus, either by making a beeping noise, activating a focus confirmation light, or flashing the focusing point that the camera believes is in focus.
The Beginner’s Guide to Photography is Haje Jan Kamps’ straightforward, no-nonsense, jargon-busting guide to taking terrific photos. It starts with the basics of exposure and moves through to getting the best out of flash and taking pictures of tricky subjects. If you’re looking for the perfect book to start off your photography career, this is it!