Definitions for "Long Lens"
Keywords:  focal, telephoto, diagonal, lens, tele
Slang for a telephoto lens (a lens whose focal length is longer than the diagonal measurement of the film used).
Term describing a lens in which the focal length is much greater than the diagonal of the film format (or standard lens) with which it is used. e.g. 300mm on 35mm format where the standard is just 50mm. (see Focal length, Standard lens & Tele)
Any lens with a focal length greater than normal; a normal focal length approximates the size relationships seen by the human eye, while a long focal length creates a narrower angle of vision, causing a larger image. A long lens alters perspective by flattening a subject into its background. (See telephoto.)
a neccessity when photographing wildlife