Convert Canon breech mount to newer bayonet

Discussion in 'Canon FD' started by NLsafari, Jan 3, 2021.

  1. OK, I have never figured out how anyone could find the B/L system at all difficult to use. If you have ever used say a Nikon F as a pro, you'll know how sloppy the mount can get after a lot of changes. The B/L system solved that.
    Ken Katz likes this.
  2. awahlster

    awahlster Moderator

    Just to put a spin on it I have used the Canon FD system since 1976 when I bought one of the First AE-1's a 35mm f2.8 100 mmf2.8 and a 600mm f8 Sigma mirror in College. I like both mount styles.
  3. That's true, and converting a breech lock lens to the "New FD" type would be an engineering nightmare, if possible at all.

    However... Sigma did make a sort of "hybrid" FD mount for some of its later Canon-fit lenses. These had a static lens body with rotating locking ring (like Canon breech lock) plus a locking catch with release button (like Canon FDn). Here's an example:

    The Sigma MF 28-85 mm f/ 3.5-4.5 MC Zoom Theta II Lens. Specs. MTF Charts. User Reviews.

    It might just be possible to add this feature to a breech lock lens, which would prevent the over-tightening problem the OP has. However it's very unlikely to be any easier or cheaper than replacing a single breech lock lens... ;-)
  4. Fujica medium format rangefinders also employed breech lock. I rarely remove the lens of my GL690 so I can’t comment on its user friendliness.
    orsetto likes this.
  5. Always wanted one of those big ILC Fujis, but ended up with Mamiya Press. ;)

    Now that you mention it, we should add Pentacon/Praktisix/Exakta/Kiev 6x6 SLRs to the medium format breech mount list as well.
  6. I maybe would have understood rebuilding a lens from BL to FDn, but these days only the time invested in thinking about such a rebuild cost more than simply buying an FDn lens. Just buy the one you have in BL in FDn and be done.
  7. Well there is actually a very easy way to convert, at least for more common lenses.

    First you sell the one you have, then you buy the one you want.
    It might even be that some collectors would rather have the older one, so you
    might be able to do it as a trade.

    Used manual focus lens prices are pretty good by now, and it will be a lot less expensive
    than even one tool that you would need for any possible conversion.
  8. KW's Praktina 35mm single lens reflex also used a breech mount system for its lenses, and it preceded any of the Canon SLRs to do so by several years.

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