Fixed focal length is in the jargon of the name for a lens whose focal length is conditionally fixed by the design and can not be change as in a zoom lens. Compared to a fixed focal length zoom lens is usually easier and cheaper to develop and produce. Prime lenses generally have a better resolution, better imaging performance and a higher light intensity.
Besides photography, prime lenses also come in video technology used.
Among photographers, there are always a discussion, whether a prime lens or a zoom lens is the better choice. In professional photography but the fixed focal length has prevailed for many applications. Due to the usually higher light intensity and because of the better picture quality it is professional standards is the result of more justice than zoom lenses, their strength, especially in the flexibility.
Areas of application and suitability
Fixed focal length lenses are used mainly when specific and characteristic picture effects of image sections are to be achieved, depending on the situation. Due to their greater potential aperture can be created in the image with fixed focal length lenses with high light intensity a less depth of field. Thus, subjects can better release from the background ( selective use of focus and blur ). Even in difficult lighting conditions, for example, to events such as concerts, church weddings or sporting events, photographers often work with high- fixed focal lengths (see also " Available Light "). By the purist nature of these lenses you fixed focal length says after also to expand the photographic view to assess motives in the outset to allow better adapted to make the environment settings ( " photographer's eye "). Due to these properties lenses are still often situational used with fixed focal lengths of photographers. A disadvantage of fixed focal length applies her solid angle of view that is not suitable in any situation and not for any motive. Why photographers use in their work usually several lenses of different classes with different properties and construction methods.