Can a Lomography Petzval 85mm with Canon EF mount be converted to Minolta MD/MC or M42?
Asked 4/16/2019
1 views
2 answers
0
I bought a second-hand Lomography Petzval 85mm in Canon EF mount, hoping to adapt it to a Minolta MC/MD camera. After looking more closely, I realized common adapters go the other way (MD lenses to EF bodies), not EF lenses to MD bodies.
Since this Petzval is manual focus and uses Waterhouse stops rather than electronic aperture control, I’m wondering whether a mount conversion is practical instead of a normal adapter.
Is there any off-the-shelf EF-to-MD or EF-to-M42 solution for this lens? If not, is replacing the EF mount with a custom M42 flange realistic, and what flange distance issues would need to be considered?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
7y ago
2 Answers
3
It is theoretically possible to reduce the barrel length by 1.46mm and replace the EF mount with an M42 threaded flange. Since the same lens is also offered in the Nikon F-mount, it's almost certain there's enough room at the back to shorten it to M42 length without getting into any internal parts of the lens. One could then use an M42 to MC/MD adapter, which are commonly available, to use the lens on a camera with the Minolta MC/MD mount.
Normally, you'd still have the problem of not being able to control the electronic aperture of an EF lens. But the lens in question does not allow the camera to control the aperture at all. It has a set of Waterhouse stops that are mechanically switched by the user.
It's also a manual focus only lens, so there's no issue with AF communications.
There are no electrical contacts at all on the back of this lens to worry about. So even though it is a newer lens with modern lens coatings, in terms of the mechanics of the rear of the lens it is essentially an old legacy type lens with modern bayonet mount flanges on the back.
I would not recommend trying this yourself, however. There are a few people/places that are well-experienced in modifying lenses from one mount to the other. I'd recommend getting on some old "legacy lens" forums and finding out if anyone knows someone in your area/country that you could pay to do the conversion for you.
Failing that, you'd probably be better of to just sell it to someone who wants the lens in EF mount and find another deal on a legacy lens with similar properties.
Originally by user15871. Source · Licensed CC BY-SA 4.0
user15871
7y ago
0
Generated from our catalog & community — verify before relying on it.
There’s no practical off-the-shelf adapter solution here. Minolta MD has a shorter flange focal distance (43.5mm) than Canon EF (44mm), so a simple EF-lens-to-MD-body adapter would need effectively negative thickness. An optical adapter would be complex and would likely change the focal length.
Likewise, EF to M42 isn’t available as a normal adapter because M42’s register (45.46mm) is longer than EF’s, leaving negative space for the conversion.
A custom mount conversion is the realistic path. Because the Petzval 85 is manual focus and uses mechanical Waterhouse stops, you don’t have to solve EF electronic aperture or autofocus issues. Based on the flange distances, converting the rear mount to M42 would require shortening the lens/mount assembly by about 1.46mm and fitting a new threaded flange. Whether this is feasible depends on the lens’s rear construction, but it appears theoretically possible.
In practice, one user found machining a custom part possible but costly enough that buying a cheap EF film camera made more sense.
Recommended products
UniqueBot
AI7y ago
Your Answer
Related Questions
Can Minolta MC/MD manual-focus lenses be used on Minolta/Sony A-mount AF bodies?
What mount does the Argus SLR use, and is it compatible with Minolta SR/MC/MD lenses?
How can I identify whether this lens uses the Minolta MD mount?
Can Sony A-mount lenses be used on a Minolta X-300 (MD/MC/SR mount)?
What mount is this Vivitar 80-200mm f/4.5, and will it adapt to Micro Four Thirds?