Prime Lens - As Alternative To Zoom Lens

As Alternative To Zoom Lens

The term prime has come to be used as the opposite of zoom; that is, a prime lens is a fixed-focal-length, or unifocal lens, while a zoom lens has a variable focal length.

A prime lens of a given focal length is less versatile than a zoom whose range includes that focal length, but is often of superior optical quality, lighter weight, smaller bulk and lower cost. In comparison with a zoom lens, a prime lens has fewer moving parts which are optimized for one particular focal length. With a less complicated lens formula they suffer from fewer problems related to chromatic aberration.

Because their optics are simpler, prime lenses usually have a larger maximum aperture (smaller f-number) than zoom lenses. This allows photography in lower light and a shallower depth of field.

A normal lens or "normal prime" is a lens with a focal length about equal to the diagonal size of the film or sensor format, or that reproduces perspective that generally looks "natural" to a human observer under normal viewing conditions.