Sentence lens

Set lens (anciently also called lens construction kit ) describes a lens of photo cameras in which, in contrast to the interchangeable lens for focal length adjustment (only) the front part can be exchanged. Historically also a set of front and rear lenses, from which the lens to be used is assembled by the photographer himself in a modular manner. Set of lenses have specially matched optical components and must be distinguished from today's front or rear-mounted fisheye, wide-angle and teleconverters as well as telecompressors, which also require an independently usable basic lens.

technology

construction

Cameras with a set lens represent a compromise between those with a permanently installed lens and those with a removable lens. With them, the rear elements of the lens together with the aperture are permanently installed. The front lenses can be removed with a screw thread or bayonet. Usually there are front parts for a wide angle , a normal and a telephoto lens for such a camera .

advantages

The advantage lies in the lower costs. The attachments are cheaper to manufacture than a complete lens because they consist of fewer lenses and they do not contain an aperture mechanism. In addition, automatic iris control can be implemented more easily, since its connection to the camera does not have to be disconnected when changing lenses.

disadvantage

The disadvantage is the limited focal length range: For extreme viewing angles, i.e. strong wide-angle or telephoto lenses, the rear lenses would also have to be adapted, i.e. replaced. In addition, no particularly bright attachments can be constructed, since all lenses must also be adapted to the focal length for this purpose . And the extension cannot be extended with extension rings or a bellows device for close-ups.

distribution

(incomplete)

Kodak

The most frequently built and therefore best-known representative was Kodak with the models Kodak Retina IIc, IIC, IIIc, IIIC, as well as the Kodak Retina Reflex , which apart from the 50 mm through the set lenses from Schneider-Kreuznach and Rodenstock then 35 mm and 80 mm respectively reached.

Canon

The Canon EX was known but not widely used . It already had fully automatic exposure control when this was not yet possible with the Canon SLR cameras with removable lenses due to the lack of transmission elements.

Historical

Lenses for plate and large format cameras were and are available separately. On the one hand, different camera models with different shutters and optics can be ordered from the manufacturer; on the other hand, lenses can be exchanged later in a suitable workshop or by the photographer himself. Mounting on a lens board created a forerunner of today's interchangeable lenses that could be exchanged relatively quickly.

The lens manufacturers produced a large number of lenses, analogous to today's offer, with different focal lengths and different levels of error correction. In addition, there were the mentioned set lenses and set lens boxes, from which the photographer could choose from a number of mounted lens groups if necessary and screw together and mount the desired lens. The rear or front base lens could often also be used independently, with correspondingly different correction and focal length. The exposure times, which were initially extreme, allowed a manual shutter with a cover, later the first mechanical shutters and integrated iris diaphragms were added, focusing was done with the pull-out.

In the present

Fixed zoom lenses have been increasingly popular since the 1980s. These cover the same focal length range as set lenses could, so that the latter are no longer relevant. Interchangeable lenses in the SLR range cover a wider range of focal lengths and light intensities than would be possible with set lenses, rear lens or central shutters. Similar constructions can only be found in special ancillary lenses (macro range, cine) or in apparatus engineering, especially microscopes.