Canon Experts - is this what I think it is? When was it made?

[Yashinoff]

This came in some ebay stuff:

It appears to be an M42 to Canon breech lock adapter.

It appears to offer automatic diaphragm operation with M42 lenses.

It looks pretty old. I have never seen one of these before. M42 to Canon adapters are common, but not this one. Was this an official Canon product? What era was it made in? Any ideas are appreciated.

 

[AgX]

Does the breech lock look like anything Canon made? I say no.

(By the way: "M42 to Canon" is ambiguous without seeing or knowing the bayonet. Or is there a common rule like "lens first-body second" ? I'm just curious.)

 

[Yashinoff]

I'm guessing that you have never seen a Canon breech lock mount?

If there is another similar mount, forgive me. It could be something else given the age and how many companies came and went way back when.

 

[AgX]

No Canon FD or FL lens with such a wavy outer of the breech lock.

 

[AgX]

It looks like a type Canon FL/FD breech lock. (The shape and location of the recesses and the location of the diaphragm activator.)

The only thing I tried to say is that its outer design does not fit to those made by Canon I've seen.
The same for its partially dark colour.

 

[Yashinoff]

Thank you for the comments. I do believe it was not made by Canon, however I'm pretty certain now it is for the Canon FL mount. Given the "zebra" pattern my best guess is that it was made in the 1960s. By who I have no idea. It's a pretty clever little bit though.

 

[AgX]

And this is the only M42 adapter to Canon FL/FD body that got a coupling for the automatic diaphragm?

 

[Yashinoff]

So far as I know. I have not been able to find any reference to such an adapter anywhere yet. Plenty of M42/Canon adapters out there, but none with this ramp/plunger arrangement.

 

[darinwc]

I've never seen anything like it. But I dont know of any canon bodies that have just-in-time or during-exposure metering. So you still are stuck with manual stop-down metering.