Digital Cameras and Combined Auto Focus

High quality photograph is comprised of many elements, one of which is objects being in good focus.

There are two different ways to focus on objects: automatic or manually. There are a few automatic focus methods and combining more than one of these is known as combined auto focus systems.

The focus can always be set manually by the photographer, but in most events the digital camera’s automatic focus feature will prove much faster and simpler. Digital cameras incorporate many various algorithms and methods to automatically calculate the right focus for the situation.

Passive and active auto focus are two such algorithms that used together create a combined automatic focus system delivering excellent automatic focus.

Passive auto focus systems use software that runs on the digital camera built-in computer. The camera performs image processing algorithms to establish a Focus Level number. The camera can determine how good the focus is and then find the best focus for the scene. There are the occasions where the passive auto focus is restricted or does not work at all.

Active auto focus systems use distance sensors that calculate the distance from the camera to the objects in the scene. Typically the camera measures the distance to the object or group of objects nearest the center of the photograph. One of the biggest advantages to active auto focus is its ability to function in total darkness.

Cameras that have the combined auto focus systems are able to choose the right system for the circumstances or cross check by running both systems at the same time.