Breech Lock mounts - are they all the same?

[bobds78]

Hi,

I was looking at some very nice lens that are "unfortunately" with Breech Lock mounts and after some digging, I didn't get much info enough to have a solid idea of Breech Lock mounts. Some lenses e.g. even big gun like Canon's FD is actually a Breech Lock mount, and I happen to have a Series I Vivitar 70-210mm made for Canon FD that I use on my E-P3.

Yes, I know how the mechanism work but what I want to know more is, can all those lens out there having Breech Lock mounts be mounted on a Canon FD to Micro 4/3 adapter? I had also read the "Camera Mount Sorted by Register" compiled by Stephen H Westin and I noticed there are a number of manufacturers producing lenses with this specific mount, the only difference I see between the various Breech Lock mounts are the Register Distances.


Can somebody care to share their experiences/knowledge on the subject? In particular the inter-mountability of the various breech lock lenses?

Thanks in advance.

Robert

[casualcollector]

Like bayonet and screw mounts, they work the same way, but they're different.

I can only speak from experience with Canon "Breech Lock" mounts. The dimensions are identical from the 1959 Canonflex series through the end of T series in the late 80s. In that period there were three aperture coupling schemes and four lens series. While all are theoretically interchangeable there are a few cases where it may not be wise to fit the late lenses on the early bodies. With regard to digital camera lens mount adapters, all Canon manual focus lenses should fit all Canon adapters as no aperture coupling is involved. Two exceptions may be the non-retrofocus 19mm FL (A mirror lockup lens) and the 38mm FLP intended for the Pellix with it's stationary, semi-transparent reflector.

Other breech lock designs are not compatible with Canon or each other. The others would be the Japanese Petri 35mm SLRs and the East German Praktina 35mm and Pentacon 6 rollfilm SLR. There's probably a few more I don't know about.

[luisalegria]

Breechlock refers to a type of mechanism, not a specific mechanism. So the dimensions, focus register and all sorts of connection details would vary from one specific type of breechlock to another.

Miranda also had what one could call a breechlock mount. Most Miranda mount lenses were made for this breechlock mount, though some presets were made for the M44 screw mount that Mirandas also had. There are Miranda adapters to some mirrorless bodies, but the Miranda register is shallow and I don't think there are adapters to any DSLR.

Rittreck/Graflex/Norita medium format SLR's had a breechlock very similar to Canon. There are no adapters from Norita to anything else that I know of.