I picked up a Soviet-made Tair-3 300mm lens at a flea market recently, and I'm at a loss to identify what kind of mount it uses. According to what I've read, most virtually all Tair-3s used M42 or T mounts, but this clearly isn't either of those.

The black bit with the orange dot on it rotates freely through about 90 degrees. I'm fairly certain it's an adapter, but I can't seem to get it to unscrew to find out for sure.

Apologies for the poor image quality - my phone camera's autofocus is utter garbage and I'm in a situation where I don't have a great deal of light available.

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2 Answers 2


What is the exact model of your particular Tair-3 lens? There were several modifications of the lens which were made by at least three different factories. Some lens versions had m39 or m42 mounts, some versions (Tair-3A) had an A-type rear mount adaptable to either m39, m42 or Nikon-F via original interchangeable rings, and some were made specifically for use on television.

Unfortunately, it's impossible to tell which one you have without more information and more detailed and better quality photos.

There is also always a possibility that the lens was custom modified to have an entirely different mount.

  • \$\begingroup\$ It's a Tair-3 4.5/300A, built for export (Roman markings rather than Cyrillic). \$\endgroup\$ Jun 5, 2017 at 7:47
  • \$\begingroup\$ @SebastianLenartowicz then your lens should be an adaptable A-type mount version. In this video a guy shows how to change an m42 to A-type mount adapter of his Jupiter-37A 135mm f/3.5 lens to a Nikon-F to A-mount one. He uses a stock КП-А/Н mount ring (pronounced as KP-A/N, which stands for "adapter ring - A-mount/Nikon"): youtu.be/P0yMgQqvSCk. Check if your lens mount looks the same as his lens does without the adapter ring. \$\endgroup\$
    – lightproof
    Jun 5, 2017 at 8:22
  • \$\begingroup\$ The mount strongly resembles the original (M42) mount on the lens he's working on. Like I said, I'm fairly certain someone just LocTited an adapter ring onto the existing M42 threading and called it a day (or worse, forced a T-mount fitting onto the M42 mount). \$\endgroup\$ Jun 5, 2017 at 8:30
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    \$\begingroup\$ @SebastianLenartowicz then your primary goal should be removing the adapter first as identifying it will probably be useless. Without some quality photos of the lens and the mount that's all I can tell. \$\endgroup\$
    – lightproof
    Jun 5, 2017 at 8:39
  • \$\begingroup\$ With enough leverage, I was able to unscrew the adapter ring. The lens itself is an A-type with M42. Works great! \$\endgroup\$ Jun 5, 2017 at 11:28

The outer breech lock ring looks like it fits a breech lock Canon FD mount or maybe the even older FL, but the inner part containing the control linkage for the aperture is missing. Is there even an aperture diaphragm inside the lens barrel?

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It might also be adapted for non-automatic use on an FD or FL mount camera. The camera would have no connection to the aperture in the lens. In such a case stop down metering would need to be used.

  • \$\begingroup\$ This is, as far as I can tell, a stock Tair-3 lens, manual aperture only, that some chowderhead LocTited an adapter onto. \$\endgroup\$ Jun 4, 2017 at 18:30
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    \$\begingroup\$ It's hard to tell much of anything from your dark, blurry photos. \$\endgroup\$
    – Michael C
    Jun 4, 2017 at 18:40
  • \$\begingroup\$ Although this answer correctly identifies the mount pictured, it ignores the fact that OP is aware this is an adapter only and wants to know what the original mount of the lens is. \$\endgroup\$
    – xiota
    Jul 20, 2018 at 9:15
  • \$\begingroup\$ @xiota which had not been revealed by the OP when the answer was written. Further, the language of the OP in the comment above indicates he suspects as much, not that he knows it. \$\endgroup\$
    – Michael C
    Jul 20, 2018 at 23:37
  • \$\begingroup\$ I'd assume a breech lock with one wider hole and a screw/pin smack in the middle quacks very loudly like FD/FL. \$\endgroup\$ Nov 17, 2019 at 12:55

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