Canon: FD on EOS? (non-RF)

[planetjoe]

So, I'm enjoying Raid's thread on WA SLR lenses on RF bodies, and I find myself fantasizing about converting my fast Canon 50s (FL 55/1.2, for example) to LTM mount with full RF-coupling.

(This happens every once in a while; eventually I'll get around to trying it or paying someone to do it for me. Sigh...)

Anyway, I head over to eBay to see about the prices on fast FL lenses and the Canon Converter B (Kevin Cameras seems to have bought out the world's supply) and I stumble across this auction, #150342956743:

http://tinyurl.com/canon-fl-ef

No relation to the seller, blah blah blah. In short, it's a Canon FL breechlock lens converted permanently to EF (i.e., EOS) mount. The seller claims it allows infinity focus, without the use of extra optics. Now, I've always understood this to be impossible, given the FD-system's flange focal length of 42mm vs. the EF's 44mm. Those dam FD-bodies were just too thin.

Does anyone know how this might be possible? It looks like the conversion was simply an EF/T-mount converter glued on to the back of the lens barrel; would simply machining off 2mm of brass allow the lens to achieve infinity focus? My Spidey Sense is tingling, telling me that it's not that simple.

Just thought you might find this interesting. Me? I'm stumped. And, apparently, I have too much time on my hands.


Cheers,
--joe.

 

[venchka]

No clue. I just keep fresh batteries and film in my Canon EF and Canon EOS 1 bodies. Use both side by side. Now, I'll admit that the 50/1.4 S.S.C. lens runs circles around it's EF cousin. If the EF body ever quits, I'll look for another BL/FD body.

 

[samoksner]

It's quite simple actually, they remove the FD mount and get an EF mount from some cheap lens... At this point, the rear of the EF mount is worked on to be the right thickness and reattached to the lens somehow... If the work is done well, the lens will have infinity focus. An issue occurs when the rear element is large enough to make it so that the new mount can't be slimmed down or something like that.

 

[planetjoe]

It's quite simple actually [...] the EF mount is worked on to be the right thickness and reattached to the lens somehow...

Thanks - for some reason I hadn't believed it would be so simple. Okay, maybe simple isn't the right word for it, but still...

Hmph. It's funny; in all the years we've been lamenting about FD/EF incompatibilities, this never seemed to come up. Of course, this would mean that the lens would be irreparably modified for EF compatibility, so I suppose that's the rub.

Still, interesting.


Cheers,
--joe.

 

[Sam N]

It might interfere with the mirror on full frame SLRs. Check that before buying. You also have to stop down the lens manually after focusing (assuming you want to focus wide open).

 

[bmattock]

It might interfere with the mirror on full frame SLRs. Check that before buying. You also have to stop down the lens manually after focusing (assuming you want to focus wide open).

I noted on a Flickr post regarding the same issue one guy who showed a photo of his 'shaved' EOS mirror to clear the rear of some of the FD lenses. I've also seen conversions using FL mount lenses, but they have the same issue with the mirror interfering on some lenses with some EOS bodies.

 

[FA Limited]

it's the cheapest way to get an 85/1.2 on an EOS body 😉

 

[planetjoe]

it's the cheapest way to get an 85/1.2 on an EOS body 😉

Ha! Isn't that the truth. I'm with Double Negative here, though, that it might be a non-starter for practical use of venerable FD glass.

I mean, why else am I keeping a T90 body around? Now, about those conversions to LTM...


Cheers,
--joe.