M42 adapter

Discussion in 'Nikon' started by michael_walter|1, Feb 15, 2005.

  1. I have an old Nikkormat FT2. I also have a few nicelenses from an old
    Ricoh Singlex TLS. The Ricoh lenses are M42 type screw on mount. I
    was looking at EBay and saw

    ADAPTER RING M42 - Nikon Bayonet

    Now, I have an adapter ring that lets me use M42 lenses on my Canon
    Rebel. However, they are not AF. Seems they would be a better match
    for the Nikkormat. Is the Nikkormat a "Bayonet Mount"? Do you think
    it would work?
  2. There is a problem with regard to using M42 lenses on a Nikon mount, even with a mount adapter, inasmuch as you cannot reach infinity focus. The answer has been to devise adapters that include a "supplementary lens," usually one that is very cheap. The result is a degradation of image quality that renders the whole experiment kind of dicey.

    Some of these adapters supposedly work without such an additional lens, but I would guess that you would sacrifice distant/infinity focus in order to use them.
  3. Hi Michael. It would work but it isn't really worth the effort. Nikon cameras are designed with a relatively large distance from the film plane at the back of the camera to the lens mount. M42 screw mount cameras are designed for a shorter distance, Canon cameras shorter still. So there is room to have a M42 to Canon adapter between the Canon camera and the M42 lens and still get the lens to focus on infinity. Similarly you could mount a Nikon lens on an M42 screw body OK. But if you try to mount an M42 screw lens on a Nikon body (ANY Nikon body, Nikkormats included) then it will be further from the film than it was designed for an will not be able to focus on infinity. Most adapters therefore incorporate a single lens element to adjust for this. The lens element has the effect of increasing the focal length by about 20% and reducing the f/stop.

    If you want to use the old Ricoh lenses, there are some nice qulaity M42 screw mount bodies out there, including many bulletproof Pentaxes.

    If you want more lenses for the Nikkormat, nearly any Nikon Manual lens will mount OK on it, as long as the lens has the rabbit ears to connect to the meter indexing pin on the camera body. I would suggest this is a better bet - sell the Ricoh lenses to help pay for it.

    Nearly every manufacturer designs a different disance from film to mount, but with respect to lens mounts, there are three basic approaches. Firstly you can have a screw thread and just screw the lens in until it stops. This is secure but takes time and the thread may wear a little over time, causing focus inaccuracy. Secondly you can place the lens in the correct orientation on the mount and rotate a ring attached to the body to hold the lens in place - the old Canon FL and FD lenses worked this way. There is no wear on the mount but it also takes time. Thirdly, and this is what nearly every modern camera, including your Nikkormat, has, is a bayonet. You fit the lens to the mount so the bayonet parts of the lens fit through the gaps in the mount, then rotate the lens home and a spring-loaded pin then holds the lens in place. You push a button on the body to release this when you change lenses. This is quick and easy and nearly every manufacturer uses this approach now.

    Regards, Ross
  4. To supplement the answers above, here is a list of camera registries:


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