Canon FD 85 1.2 SSC AL - aperture link

pavko · Joined: 31 Jan 2011 Posts: 216 Location: PL

There is a saying that things that got into internet stay there - which is mostly true except for really valuable pieces of information. I did my research but all pages dealing with breach-lock version of the lens either no longer exist or miss pictures. So I'm asking for help here (as maybe some of you have pictures stored in your own archives). What I need is either exploded view explaining how aperture and links work or pictures from conversion to (so popular in the past) EF mount. My goal is to make direct connection of aperture ring with aperture mechanism as it is not going to be used with FD gear any more (there is slight chance of T70 in aperture priority mode). My copy of the lens is not collectible, severally scratched (both body and coatings), beaten from front and with semi-frozen aperture. I want to save it as it still delivers what most important in this hobby - great picture quality. Any help really appreciated.

cooltouch · Joined: 15 Jan 2009 Posts: 9109 Location: Houston, Texas

I have a copy of this lens. Mine is definitely not a "beater" though. Not mint, but very clean, nonetheless.

What you're trying to do regarding the aperture being linked to the aperture ring is not difficult, though. Once the breechlock ring is rotated to its "closed" position, the larger lever on the rear of the lens can be locked back -- rotated counterclockwise until it locks into place. Once you do this, the aperture is manual and opens and closes as you turn the ring. It will stay in this condition until you unlock the lever from its locked-back position.

So there's really no need for surgery or reconfiguration or anything. All you have to do is concentrate on the mount conversion. There are quite a few sources for this out on the internet, from what I hear.

I have a spare FL 55mm f/1.2 that I'm thinking about converting over to EOS mount. I've been playing around with an M42 to EOS adapter to use with it. Nice thing about it is it drops down around the rear element and fits great. I believe this rear element is the same size as the 85's rear element. It would be a non-destructive conversion. Only thing required would be to drill some holes into the M42-EOS adapter, then countersink them. Then mount the screws already there in the lens into the adapter first. I think they should be long enough without running into problems. So anyway, all that's required if you use the M42 to EOS adapter is machining off some material from the flat mating surface -- about .020" or so? I don't recall now. I have the calcs around here somewhere. And I think this same conversion can be done just as easily with the 85mm.

pavko · Joined: 31 Jan 2011 Posts: 216 Location: PL

Maybe I have not explained myself well enough - my intention is not to convert it to EF (it stays with FD mount) but to change way aperture operates (as someone tampered with original links and they are not operational). Because of that I'm searching for photo rich relation from EF conversion. During such conversion you have to completely remove back of the lens with levers, transplant last optical element to EF mount and also create link between aperture ring and aperture mechanism. And that is what I'm after.

cooltouch · Joined: 15 Jan 2009 Posts: 9109 Location: Houston, Texas

Actually, as I mentioned above, even though you don't plan to convert to the EOS mount, you don't have to do what you're describing to convert to it. All the conversions I've seen have just involved mounting an adapter to the rear of the lens, after removal of the breechlock ring. So with the conversions I've seen, the aperture mechanism has remained unaffected. Thus I think you would be better off trying to restore the aperture mechanism to the way it operated originally instead of trying to modify a modified arrangement.

pavko · Joined: 31 Jan 2011 Posts: 216 Location: PL

I did a little bit more of research and what is crucial for project is pictured here:
https://twitter.com/EdMikaAdapters/status/281858409702232065
Looks like doable (even without milling machine). Based on the fact that aperture mechanism is broken by design and then broken by previous owner(s) I'm now strongly convinced to replace it.

cooltouch · Joined: 15 Jan 2009 Posts: 9109 Location: Houston, Texas

The Ed Mika kit will have components that replace the do-it-yourself milled M42 adapter, so yeah, no milling will be necessary. He produces high quality kits. I'm sure this will work well.