Leica LTM LTM Adapters on Leica M

Leica M39 screw mount bodies/lenses
David Murphy

David Murphy

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I've been using my M2 lately with some LTM lenses using Leica and Voigtlander adapters. I may be imagining this, or perhaps I don't have enough images yet to make a sound judgement, but my impression is that the image sharpness is slightly lower than when the lenses are used on a pure LTM camera. The lenses in use have been mostly wide angle 28-35mm F2-F3.5.

Just how good are LTM adapters at preserving the focal plane location? Anyone else have any problems with this?
 
Which adapters are you using, David ?

They can be quite different, which matters particularly for wide angles.

I have had only reliably good results with original Leica adapters. And I use many non-Leica lenses, so I assure you, the brand doesn't matter to me.

Roland.
 
Well I need to check, but at least one is a Leica-made adapter -- the others are Japanese as I recall. I'm beginning to like the idea of using only native bayonet lenses on my M2.
 
Why would adaptors matter more on wide angle lenses, Roland? Don't they have more DOF at each f stop than normal and longer lenses at those same f stops?
 
FrankS said:
Why would adaptors matter more on wide angle lenses, Roland? Don't they have more DOF at each f stop than normal and longer lenses at those same f stops?
Click to expand...

DOF and focal plane sensitivity are two different things, Frank. Wide angles are much more sensitive to focal plane shifts than longer lenses.

Roland.
 
If that's the case then I've learned something new! :)

Focal plane shift via an adaptor is somehow different than moving the lens with the focus helical?
 
FrankS said:
Focal plane shift via an adaptor is somehow different than moving the lens with the focus helical?
Click to expand...

No that's the same. But the relations are different.

Take a 90 and a 35mm lens. Change focus from infinity to 1m. They both (physically) get longer, FOV decreases. But the 35mm lens, in absolute terms moves only very little (2-3mm, maybe ?) from infinity to close up, much less so than the 90 (a cm maybe ?).

Roland.
 
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Ah, thank you! I don't mind being shown that I'm wrong about something because it means I've learned something.
 
It makes sense ... now.
I prefer using LTM lenses on LTM bodies, and also FSU LTM lenses on FSU LTM bodies.
 
It turns out that the adapter that seems sharper was a Leica-made one. I'll check the run-out of the adapter thicknesses with a micrometer and report back.
 
Off brand adapters sometimes are made not exactly 1 mm thick.

I have measureed my Leica and CV ones and they are perfect.
 
My experience with a 50mm Jupiter and a Leica-adapter on my M6 is that there are no differences in terms of sharpness or focussing or anything else to my summicrons with the direct thread mount.

Regards, Axel
 
I've noticed that original Leitz adapters mount more easely on the camera. Mouting my cv-ones allways make me fear that I will damage the camera. I have to mount the cv-ones exact parallel on the camera, while I can put on the Leitz-ones as easy as an original bayonet Leica-M lens.
I will replace my cv-adapters with Leitz-ones as soon as I can find them.

Erik.
 
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As I understand it, the adapter doesn't have to be exactly 1 mm thick. The rangefinder is coupled to the thing that moves forward & backward inside the main barrel; so if the adapter were too thin, you would only loose a few cm in close-focus distance.

Greetings,
Dirk

Ronald M said:
Off brand adapters sometimes are made not exactly 1 mm thick...
Click to expand...
 
Again, the movement of RF cam and lens barrel are not the same for either wide angle or tele. For a wide angle the cam moves more than the lens barrel. If the adapter is only a little off, you will loose noticably resolution at infinity.
 
delft said:
As I understand it, the adapter doesn't have to be exactly 1 mm thick. The rangefinder is coupled to the thing that moves forward & backward inside the main barrel; so if the adapter were too thin, you would only loose a few cm in close-focus distance.

Greetings,
Dirk
Click to expand...

This is true only for 50mm "normal" lenses where the optics move 1:1 with the RF cam. As Roland stated, When a translation is involved, the difference in thickness will knock the focus off.
 
After a good nights sleep, and making a little drawing, it fainally makes sense to me.

Greetings,
Dirk
 
I agree. If you have the time and resources to plan, I believe that its best to reduce the variables e.g. manufacturing compromises. Sometimes circumstances force compromise but I would never buy an adapter as part of a kit.

Ray

raid said:
It makes sense ... now.
I prefer using LTM lenses on LTM bodies, and also FSU LTM lenses on FSU LTM bodies.
Click to expand...
 
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