Lens Adapters TO M42 mount??

Discussion in 'Pentax' started by ansarmsmith, Dec 24, 2017.

  1. I recently purchased a Krasnogorsk-3 16mm camera, I have a few m42 mount lenses, but I wanted to adapt my Bronica PG mount lens to the M42 mount. I could imagine the Bronica lens, or any high quality lens would do wonders on 16mm so I wanted to figure out how it could be down.

    Doing my research I found that Fotodiox makes lens adapters for Bronica PG lenses to be mounted on Various other mounts, but not for M42. I further found that in theory, since the flange distance is much larger than M42 mounts, it wouldn't be necessarily impossible. But found it quite difficult to find adapters TO M42 mount, as I know it's an old mount that not many people have had the motivation to adapt lenses to, usually just the other way around. Also since the flange distance for M42 mounts is longer than a lot of other common shorter flange mounts, that adds to the reasoning for there not being a lot of adapters out there TO M42.

    But luckily I found that there are some Nikon F TO M42 mount adapters lingering around ebay. If I could adapt the Bronica PG to Nikon F then to M42, would that work?

    (Hopefully, this is the right thread topic, let me know if not)
  2. Sure, why not?
    I am not ultra familiar with F mount, I am aware that it has a comparably great flange distance but better make sure the F to M42 adapter permits focusing to infinity. If that is the case get it, stack it and have fun.
  3. M42 lenses cannot be adapted to Nikon F and maintain infinity focus. The respective dimensions don't allow it.
  4. I said Nikon F TO M42, not the other way around
  5. Yeah this will probably work. My only concern is that: in the description of the F to M42 on ebay, it says "Macro Shooting Only". Why would an adapter do this? Does that mean it is not the right flange distance? I know Nikon F has a further distance to M42, so what's so hard about getting that right?
  6. I think the one offered on Amazon did not list that, but I couldn't find any clear facts within an admittedly quick search.
    You got me going. I have a Spotmatic and some Sigma screwdriver Nikon AF lens and found out: "M 42 cameras have a damn narrow hole." It seems challenging / (takes a bit of force?) to freelens the Sigma into the Spotmatic so they'll be mount on mount. Nikon added so much stuff that doesn't interest you to the F mount over the years. There is an aperture lever sticking out and vis a vis a block with electric contacts all that stuff has to go into the camera body and M42 seems a tad too narrow to let it through. and adapter would need space inside the M42 mount too and not be very useful if only the most primitive F mount variants could be put onto it.
    During my freelensing attempt I had most distant focus about an arm's length away, zoom set to 70mm.
  7. Although it references Canon EOS specifically, the lens flange to image plane distances are given at Bob Atkins essay and you can work out which distances are compatible with adapters that focus to infinity without a lens built in.
    The Nikon F mount at 46.5mm is easy to adapt to cameras with shorter flange-plane distances, but many other popular lens mounts will not take Nikon lenses with infinity focus without a lens (which is usually going to affect IQ enough to make the exercise moot).

    There is more general discussion at B&H (Introduction to Lens Mounts and Lens Adapters)
  8. JDM is overlooking the 2nd dimension. The EOS mount is among the biggest holes of them all. Its hard to push an M42 bodytowards the rear, not "flange" end of the wider F-mount bayonet.
  9. And this is not an accident...

    Without getting into details on specific combinations, I was merely pointing out that the Nikon F is more adaptable to other mounts than the other way around.


    "Under capitalism, man exploits man. Under communism, it's the other way around"
  10. I did some searching on eBay and I found only one adapter that will work with Bronica PG lenses:

    eBay item number: 362207886715

    It's for mounting a Bronica PG lens to a Canon EOS body. So I did a search for M42 camera to EOS lens adapter there, and got no hits.

    A bit more searching and I discovered adapters for Bronica S2/EC/ECTL to fit M42 lenses, for Bronica SQ and ETR lenses to fit Nikon F, but nothing for PG lenses.
  11. paul ron

    paul ron NYC

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