Canon Lens Mount Converter A

mtnbkr · Feb 5, 2022

Can anyone tell me about these? I just found out about their existence, but can't find much info on them except for a comment they don't allow focus to infinity. Another statement on KEH indicates it's for macro use. Aside from two simple sentences, I can't find much else.

I want to use one to mount the L39 15mm lens I have for my Canon VT on my FT SLR. Does not focusing to infinity preclude using hyperfocal?

Chris

Mackinaw · Feb 5, 2022

The Lens Mount Converter A does allow L39 lenses and accessories to be mounted to a Canon breechlock SLR. You can mount an L39 lens, but it won't focus to infinity. It was primarily designed for L39 close-up tubes and other closeup accessories.

Jim B.

tokam · Feb 6, 2022

I have the opposite converter, Canon converter B, which allows fitment of FD/FL lenses to LTM bodies. I have / had intentions of buying an LTM body and using my FD wide angle lenses on it. Zone focus, of course, but with lenses from 20mm to 28mm the depth of field should cover all eventualities. Without an external viewfinder composition could be tricky - these lenses are very generous in their coverage.

mtnbkr · Feb 6, 2022

Mackinaw said:
The Lens Mount Converter A does allow L39 lenses and accessories to be mounted to a Canon breechlock SLR. You can mount an L39 lens, but it won't focus to infinity. It was primarily designed for L39 close-up tubes and other closeup accessories.

Jim B.

I wasn't aware L39 close-up equipment existed. I would have though better macro gear was available for the SLR in FL/FD mount.

The lens won't focus to infinity, but with one with such great DOF like the 15mm, wouldn't infinity be sharp if I stopped the lens down? Or is the focus point so near that it wouldn't work at all?

What a weird adapter if that's all it's good for...

Chris

randyB · Feb 6, 2022

Nothing "weird" about it at all. Back in the early 70's Canon had an extensive system for close-up/macro/micro photography. This system was fleshed out with the introduction of the original F-1 system. It was aimed at the Scientific/Government/University/Research communities. Average photographers benefited by having a system to match their needs, they just bought the parts that fit their needs. I still use my bellows and ltm tubes along with my 50mm and 100mm macro lenses for closeups/macro work.

gone · Feb 6, 2022

And Leica made those rangefinder cameras for close up work w/ no rangefinder, no viewfinder, no nothing. I think they're highly sought after too. That's Leica for you. Only Leica would call leaving something out an upgrade, so that it costs you more money.

mtnbkr · Feb 6, 2022

randyB said:
Nothing "weird" about it at all. Back in the early 70's Canon had an extensive system for close-up/macro/micro photography. This system was fleshed out with the introduction of the original F-1 system. It was aimed at the Scientific/Government/University/Research communities. Average photographers benefited by having a system to match their needs, they just bought the parts that fit their needs. I still use my bellows and ltm tubes along with my 50mm and 100mm macro lenses for closeups/macro work.

What seems weird to me is that I'd expect Canon to have similar macro gear for their SLRs, negating the need to adapt LTM gear to their FL/FD systems. I assumed the LTM macro gear to be less diverse and less common than what was available in the SLR lines. Just looking here I see lots of macro options for FD.

Anyway, the point of my OP was more around being able to get infinity in focus by stopping down since I can't manually focus to infinity with the adapter. I'd really like to try my Voigtlander 15mm on my FT, but it's not sounding promising.

Chris

reddesert · Feb 6, 2022

It absolutely, 100%, will not work for infinity. The flange to film distance of the L39 mount is 28.8mm and of the FD mount is 42mm, so even if the adapter had zero thickness, the lens would be 13.2mm too far out. You can never make this up by stopping down. The lens will wind up being focused maybe a couple inches away from the front element.

Canon did make FD mount macro gear for their SLRs, but because there were already M39 macro tubes, enlarging lens, etc out in the world, they made an adapter for the convenience of their users.

randyB · Feb 6, 2022

The LTM tubes and adapters that I speak of were sold for the SLR cameras right along side their FL/FD extention tubes and bellows, it was a rather extensive system designed to cover many, many different senarios. Nikon, Minolta, Pentax, Leica and Olympus and others also had extensive closeup systems, just not quite as complete as Canon.
Simple logic should tell you that a lens designed for 27.8mm or 28.8mm flange focus would never be able to focus to infinity on a camera with 42mm flange focus. I suggest you try the Canon FD super wides, they are very impressive

eli griggs · Feb 6, 2022

I have the Canon A converter and Leica m39 extension tubes, but no Leica lenses, using FSU and Sun lenses.

I've never found a reason to use these for closeup work, Canon kit being superior, but keep them in case I decide to carry a m39 kit with a single Ftbn or F1 Canon kit.

The Leica m39 tubes/lenses can be used with m39 enlarger boards, too.

Canon Lens Mount Converter A

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