Focus peaking is a focusing aid that is available in live preview or electronic viewfinders on digital cameras. It places a white or colored highlight on in-focus edges within an image using an edge detect filter. This feature is based on the principle that the sharpest areas of an image have high contrast, which appears on the Live View display as either a white or colored highlight on the edges and textures of objects. An algorithm analyzes the image in real-time, and when an item comes into focus, the sharp edges create an intense exposure in that specific area of the picture. Focus peaking allows the photographer to focus manual lenses with greater speed than the typical Live View method, making it ideal for scenarios where it’s challenging to quickly assess what areas are in focus.
Some external monitors and some image organization programs can also perform focus peaking separately from the camera body. Focus peaking is sometimes referred to as "focus assist" or "peaking highlights". Although focus peaking is fast, it is considered to be inferior to digitally zooming in, and it is not recommended when taking pictures with either a very narrow or very wide depth of field.
