I've been reading up on Minolta Rokkor 58mm f/1.2 to Canon mount conversions. Sadly, I shoot Nikon (entrenched too deep in their gear to switch now), and there is practically no documentation on the Internet about Nikon mods. All I've found are two really old forum threads containing claims that it's been done.

I'm aware that the process is theoretically the same for Nikon and Canon, but flange length for Nikon is 46.5mm, substantially more than 43.5mm for Minolta. Does this mean it's impossible to achieve infinity focus even on a cropped sensor Nikon?

Has anyone done this mod? What was your focusing range and how thin did you have to make your spacer? If it's not too difficult to make it to 25-30 feet instead of infinity, it sounds worth it considering the nature of this particular lens. Probably won't be running around shooting landscapes with it.

  • \$\begingroup\$ Thanks for the link, drewbenn. Would you recommend any particular bodies? \$\endgroup\$
    – rfgon
    Commented May 24, 2012 at 1:48
  • 1
    \$\begingroup\$ Well, I gave up and got a used Sony NEX-3. Not excited about the lack of viewfinder and buttons, but I can't wait to put my neglected vintage glass in action! \$\endgroup\$
    – rfgon
    Commented May 30, 2012 at 1:35

1 Answer 1


Okay, after some digging, I found a Flickr discussion that partially answers my question: http://www.flickr.com/groups/nikon_d300_users/discuss/72157624796707182/

Someone claims that a ~50mm M42 wearing a thin glassless Nikon adapter can have a max focusing distance of 2.5m.

The question of what can be achieved via more invasive modification, such as replacing the M42 mount entirely or machining/sanding down bits of the lens, and how far you can go without impairing lens functionality or letting the mirror hit the rear element, is still unanswered.


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