Focal length
n.phr.
Subject Field: Photography, Optics

Focal length refers to the distance from the center of a lens to that point behind it where the incoming light rays cross the optical axis to form a sharp image on a plane still farther back. Stinson			See Also Zoom lens Wide-angle lens Telephoto lens Focus Bibliography Index Home Conceptual tree
Context: The perspective of the view remains the same from person to person. Humans have eyes of the same focal length. There is, therefore, a danger that a director will be unaware that the world can look different when seen through different optical equipment. Crisp Attestation: 2 Lunghezza focale Reliability: 3