Leica M to LTM adapter problem

[alphonse2501]

Recently I bought one Leica M to 39mm adapter for mynew Leica M3. After I mount both adapter and Industar-22 on on M3, I find lens become not infinity from viewfinder. Later I make checking how Industar-22 mounting between Zorki-1 and adapted M3, I notice Industar-22's mount of infinity locked position from Zorki-1 is shift to counter-clock wise a little on adapter ( infinite tab's position shifted from 9 o'clock to 7 o'clock compare with Z-1). My Summitar and Summarit have similar problem so I doubt the adapter I bought probably not accurate enough...


Voigtlander adapter is back-ordered on B&H and Adorama, so option I have now are cameraquest and Fedka.com.

[Godfrey]

Originally Posted by alphonse2501

...
Voigtlander adapter is back-ordered on B&H and Adorama, so option I have now are cameraquest and Fedka.com.

I have three of the Voigtländer adapters that I bought from Steve Gandy @ CameraQuest (two 50, one 28 mm). They work perfectly on all four of my M-bayonet bodies.

Since I don't own any LTM bodies, I buy one for each lens, fit it, and don't remove it again.

[V-12]

Don't be confused over Voigtlander adapters which are for mounting a CV lens square on an M body, and genuine LTM adapters that are meant to mount a LTM lens off centre on an M body.

On LTM bodies the lens when screwed on is mounted off centre, this is because if an accessory viewfinder is used you wouldn't be able to easily see the focus scale if it was at the top. So LTM lenses are nearly all off centre on the LTM body. Additionally the 'throw' of the focus ring of LTM lenses is designed to start and end so your fingers don't get in the way of the rangefinder.

So, if you mount a genuine LTM lens on an M body using the correct adapter the lens will be mounted off centre. This is also to ensure the throw of the focus ring still keeps your fingers out of the viewfinder and rangefinder windows. It makes no difference to focusing or accuracy, but your focus scale is offset. If you use a CV adapter on an M body using a genune LTM lens, and it ends up mounted square, you stand a good chance the focus throw will get your finger in the viewfinder at the closest distance.

So don't blame the adapter manufacturer for inaccuracy, LTM lenses are supposed to be offset on both an LTM body and therefore also an M body.

[alphonse2501]

I see...but rangefinder do not coincide on infinity on my adapter.

[CNNY]

Originally Posted by alphonse2501

I see...but rangefinder do not coincide on infinity on my adapter.

This is common with a lot of the cheap adapters on eBay. They will focus a little bit past infinity to be 'safe'. You should be able to shim it with some tape on the screw mount side on the adapter. Not that elegant, but if you keep the lens screwed on you shouldn't see it.

[funkydog]

FSU LTM lenses were built to work correctly on FED and Zorki bodies. They didn't focus right on Leica LTM bodies and M bodies didnt exist at that time. FWIW I have two Industar lenses and both focus past infinity on M mount bodies regardless of adapter quality (I have good and dodgy adapters). Perhaps you can unscrew the lens from the mount by a quarter turn and shim it with a sliver of wood. Then take photos of distant objects with the aperture set wide open and lens focused at infinity. Repeat the process until the focus is where you want it to be. Dont get too bent out of shape over rf patches not lining up for FSU lenses.

[alphonse2501]

CNNY and funkydog are indicate "past infinity", however mine is "before infinity": all my lens just needs 1/6 or less turns to archive infinity.

[funkydog]

The only other thing I can think of is that the focusing helical is messed up. You can disassemble and realign the helical by removing the two little vertical pins. The f-stop scale on the helical doesn't line up with the distance scale on the flat ring if the lens has been taken apart and put back incorrectly.

Btw dude, perspective. This is a $30 lens, $15 for shipping. FSU lenses are a crapshoot. Life is too short to obsess over a cheap lens that is possibly wonky. LTM-M adapters cost more. Replacing the adapter with another and keeping the lens is .. false economy?

[Godfrey]

Originally Posted by V-12

Don't be confused over Voigtlander adapters which are for mounting a CV lens square on an M body, and genuine LTM adapters that are meant to mount a LTM lens off centre on an M body.

On LTM bodies the lens when screwed on is mounted off centre, this is because if an accessory viewfinder is used you wouldn't be able to easily see the focus scale if it was at the top. So LTM lenses are nearly all off centre on the LTM body. Additionally the 'throw' of the focus ring of LTM lenses is designed to start and end so your fingers don't get in the way of the rangefinder.

So, if you mount a genuine LTM lens on an M body using the correct adapter the lens will be mounted off centre. This is also to ensure the throw of the focus ring still keeps your fingers out of the viewfinder and rangefinder windows. It makes no difference to focusing or accuracy, but your focus scale is offset. If you use a CV adapter on an M body using a genune LTM lens, and it ends up mounted square, you stand a good chance the focus throw will get your finger in the viewfinder at the closest distance.

So don't blame the adapter manufacturer for inaccuracy, LTM lenses are supposed to be offset on both an LTM body and therefore also an M body.

I've never heard of nor seen this before. I bought Leica LTM to M-bayonet adapters for all my LTM lenses back in the day when I inherited a IIIf kit with four Leica lenses and needed to adapt them to my M body. All the lenses mounted direct on center and the focusing index was at the top of the lens, as normal, on the M. Same for using the Voigtländer LTM to M body adapters. All lenses focused to infinity with both, and the focusing tab, etc, have always parked into the same relative positions.

[alphonse2501]

I managed to get a free adapter that made by brass. My Summitar and Summarit LTM now perfectly match the infinity. collapsible Industar-22's focusing tab hit lens release button so it only make 20 meter so far on focusing scale. Industar-61 LD can be mount, however it still somewhat under infinity from rangefinder's patch. It probably due focusing helical between FSU and Leica?


The last lens I will want to try is my rigid Industar-50, so I will have result if I can back to my house this weekend.



At the end I feel my Kiev 4 is less adaptable as Leitz/FSU LTM but it has less trouble since choose of contax mount lens are far less than LTM/M lens.
(Of course except pre-war / post war mount.)