Condition: Excellent

Aroma Auto 2X Tele Converter in case M42 Screw fit

Excellent cosmetic and full working condition c/w front lens cap, case

General 2 X converter Information

The 42mm screw mount was introduced in 1949 with the Contax S 35mm SLR made by the East German firm VEB Zeiss Ikon. It was also adopted by the East German firm KW on their Praktica range of cameras, introduced around the same time as the Contax S. In the early 1950s the mount was also used by the West German firm Wirgin on their Edixa Reflex range of cameras. Later (1957) it was adopted by Asahi for the Asahi Pentax family of SLRs which sparked the Japanese camera industry. In the 1960s several other Japanese manufacturers also adopted the mount for their new 35mm system cameras. It was also used by the Russians on Zenits from the second production run of the Zenit E onwards.

In 1956 the Contax F introduced an internal aperture stop-down pin located at 6 o'clock inside the lens mount. Versions of this innovation were adopted by practically all subsequent users of the M42 mount (with the exception of preset or T mount lenses), though early adaptations varied slightly by manufacturer. By the early 1960s the diaphragm actuation mechanism had been standardized as many more companies began using the mount for their system 35mm cameras. Praktica was once again an early adopter.

In 1959 both VEB Zeiss Ikon and KW were absorbed into the new East German Pentacon camera manufacturing consortium. All subsequent Pentacon 35mm SLR cameras (most of which were continuations of VEB Zeiss Ikon or KW lines) of the 1960s used the M42 mount.

Despite the standardization of the diaphragm actuation mechanism, there was no industry standard for communicating the aperture ring position to a TTL light meter. Before screw-mount lenses faded from the scene, Mamiya, Pentax, Fuji, Olympus, Zeiss Ikon and Pentacon all introduced mutually incompatible systems to permit open-aperture metering; but the majority of TTL metered M42 cameras simply use stop-down metering instead.

In the 1970s, as camera electronics and in-camera metering systems rapidly became much more sophisticated, requiring very accurate mounting tolerances to establish electrical contacts between a camera body and lenses, the technical limitations of a screw-mount lens system quickly rendered the M42 mount obsolete. The M42 mount was progressively replaced by bayonet mounts by all the manufacturers that used it, except on some Zenits. Recently Cosina Voigtländer reintroduced a 42mm screw mount SLR with the Bessaflex TM (2004).

This mount is also called Universal screw mount, Pentax screw mount, Praktica screw mount, or M42 for short. The mount is also sometimes referred to as the P-Mount, which homogenizes the various Pentax, Praktica, or Pentacon associations with the mount.

Glassless adapters have been marketed that will allow M42 lenses to be used on bodies with the Pentax K-mount, the Canon FD or EF mount, the Nikon F mount, the Minolta MD or α mount, the Olympus OM mount, the Konica AR mount, and other 35mm SLR mounts. Some manufacturers wanted to maintain continuity and offered user-friendly adapters with the ability to push the aperture pin automatically for stopping-down. Those adapters were made for cameras with Fuji X-mount, for some cameras with Rollei QBM-mount (e.g. Rolleiflex SL35), and for the Mamiya NC1000(s). Adapters are also available to use M42-mount lenses on virtually all digital mirrorless interchangeable lens cameras as well.

Camera House Price: £8.00

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The Aroma Auto 2X Tele Converter M42 Screw fit in case is shown in Lenses.

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