Subject-Detection Autofocus
An autofocus feature that recognises people, animals, birds or vehicles in the frame and keeps them sharp as they move.
On this page 3 sections
Autofocus is how a camera makes the subject sharp. Older systems focused on whatever sat under a small point in the frame, and that point had to be kept on the subject by hand. Subject-detection autofocus recognises what is in the picture, such as a face or an eye, and then follows it across the frame while the camera shoots.
How it works
The camera's processor compares the image from the sensor with patterns it has learned for different subjects. Once it finds one, it places the focus point on it and keeps updating the point as the subject moves.
Subjects it can recognise
- People: faces and eyes, and on some cameras the head and body, so focus holds when a person turns away.
- Animals: usually pets such as cats and dogs.
- Birds: including birds in flight on capable cameras.
- Vehicles: cars, motorbikes, trains or aircraft.
What it does not promise
Detection does not guarantee that every shot is sharp. It works best in good light and with a clear view of the subject. In very dim light, against strong backlight, or when the subject is small or partly hidden, it can lose track. The lens also matters, because a slow-focusing lens can limit a capable camera.