Polttovälillä

Polttovälillä is a Finnish term that translates to "focal length" in English, commonly used in optics and photography. It refers to the distance between the optical center of a lens and the focal point, where parallel rays of light converge to form a sharp image. This measurement is crucial in determining the field of view and magnification of a lens.

In photography, lenses with short focal lengths, typically below 35mm on a 35mm film equivalent, are considered wide-angle lenses. They capture a broader perspective and can make scenes appear larger. Conversely, lenses with long focal lengths, often above 70mm, are telephoto lenses. They magnify distant subjects and have a narrower field of view. Lenses with focal lengths around 50mm are often referred to as standard lenses, as their field of view closely approximates human vision.

The focal length is usually expressed in millimeters (mm). A lens's focal length is a fixed property, but zoom lenses allow for a variable focal length within a certain range, offering flexibility in framing shots. Understanding polttovälillä is fundamental for photographers to control perspective, composition, and the overall aesthetic of their images. It directly impacts how much of a scene is captured and how objects within that scene appear in relation to each other.