Auto focus (AF) is a feature on many digital cameras that automatically adjusts the focus of the lens to ensure that the subject of the photograph is in sharp focus. Auto focus is a convenient feature that allows the photographer to quickly and easily capture sharp images without having to manually adjust the focus of the lens.
The camera will use the focus points that you see when you look into the viewfinder. These focus points are what the camera will use to determine where to focus. Contrast is instrumental in achieving sharp images when using auto focus. The camera may have difficulty focusing in areas of no or low contrast. Higher-end cameras will often have more focus points and they will have more coverage across the frame.
There are several different types of auto focus systems available on digital cameras, each with their own benefits and drawbacks. Some common types of auto focus include:
Single-point AF: This type of auto focus uses a single focusing point to determine the focus of the lens. The photographer can specify the exact area of the scene that they want to be in focus. Typically in this mode you will need to press the shutter button half-way down until you lock in to focus before you can complete the capture. Your camera may beep to indicate focus has been locked on. Single-point AF is a good option for photographers who want precise control over the focus of their images. It is best used for static or slow-moving subjects such as portrait photography.
Continuous AF: This type of auto focus is designed to track moving subjects and keep them in focus as they move through the frame. Continuous AF is a good option for photographers who are shooting sports or other fast-moving subjects such as wildlife. Unlike Single-point AF the camera will continue to adjust focus as the subject moves. A note for Canon photographers, you may see this as AI-Servo.
Face detection AF: This type of auto focus uses facial recognition technology to detect and focus on human faces in the scene. Face detection AF is a convenient option for portrait photographers or anyone who wants to ensure that their subjects' faces are in sharp focus. Keep in mind things like hats and sunglasses may interfere with the subjects ability to recognize a face.
Eye AF: This type of auto focus is similar to face detection AF, but it is specifically designed to focus on the eyes of the subject. Eye AF is a useful feature for portrait photographers who want to ensure that their subjects' eyes are in sharp focus. Many cameras now also recognize animal eyes and can be good for wildlife photography. This can be thrown off by animals with dark fur and dark eyes
Overall, auto focus is a convenient and useful feature for photographers of all levels as it allows the photographer to quickly and easily capture sharp images without having to manually adjust the focus of the lens.
Comments