Contrast detection is one of the methods of automatic focusing, also known as autofocus. This system works by having the camera's processor analyze the image directly from the image sensor, searching for the spot with the highest possible contrast, meaning the greatest difference between neighboring light and dark points. Maximum contrast means maximum sharpness, so once the camera finds it, the scene is in focus. To find this point, the lens must slightly move past the point of highest sharpness and then return to confirm that it has found the correct spot. This search process can sometimes be visible on the display and tends to be slower, especially in low light or with moving objects. This technology is commonly used in compact cameras, mirrorless cameras, and also in digital SLR cameras when focusing in live view mode, i.e., when shooting via the display.
