Tarkennuspiste

Tarkennuspiste, literally “focus point,” is a term used in photography to refer to the specific area of a scene that a camera’s autofocus system uses to establish sharpness. The chosen piste determines the distance at which the lens is set to focus, shaping the image’s plane of sharpest focus and its depth of field.

In practice, tarkennuspiste is indicated in the viewfinder or on the LCD as a small marker—such as a square, dot, or crosshair. Photographers can select a single tarkennuspiste for precise control or use multi-point or zone AF, which employs several points to determine and track the subject, helpful for off-center subjects or movement.

Selection methods vary by camera and may involve arrows, a joystick, a touch screen, or a dedicated button. In portrait work, photographers often place the tarkennuspiste on the subject’s eyes. Modern cameras frequently offer face or eye detection that automatically selects the appropriate focus point.

The choice of tarkennuspiste interacts with autofocus technology, which may be phase-detection, contrast-detection, or a hybrid system. It also interacts with exposure and lens settings: focusing at a close distance with a wide aperture yields a shallow depth of field, while focusing farther away or using a smaller aperture increases depth of field.

Etymology: tarkennuspiste is a Finnish compound of tarkennus (focus) and piste (point). The concept is central to camera operation and manual or semi-automatic focusing workflows.