Infinity focus with M lenses

[jaapv]

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2 hours ago, mada9909 said:

Yes, Jaapv, indeed i just bought SL2S and noticed this issue after mounting Leica M-L adopter. 

Thanks for the reply. 

so, the solution is that using a cheaper adopter made in China instead of original Leica's if you want to get infinity focus with M lens? 

 

Umm, with a shorter adapter you do get infinity. It just goes a fraction beyond infinity to the stop. Which is quite normal, many longer lenses do so natively. It is a simple matter of compensating for expansion of the barrel of the lens at high temperatures. Leica cannot know whether you mount a 18 or a 135 lens on the adapter,( or even stack it for much longer lenses), so they have to accomodate for the longest possible lens. Even with a Noctilux  or even worse, a Summilux 75 or Summicron 90 an added expansion can cause an infinity problem. So no, it is not an issue but good design to ensure that any lens can reach infinity in all conditions.BTW, infinity is easily focused on an SL. It is, after all, an EVF camera…

[Mak67]

Well, more wide you go, and more problem you'll have ... I had a very bad expérience using the Wate on the SL2.

Real problem is with FLE lenses, because wrong Lens position ( due to wrong adapter focal flange) , then the FLE système get out of it's optimal position, then overcorrect or undercorrect ... Make it worst than not being corrected.

Keeper in mind, all Leica adapters are not adjust the same way, i had to buy 3 and kept the just one, there were a huge différence between the 3.

[frame-it]

On 12/1/2023 at 6:19 PM, jaapv said:

proves that it is not a tolerance or manufacturing issue but a design specification. 

yes

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madapter_l.pdf

[BernardC]

5 hours ago, Mak67 said:

Real problem is with FLE lenses, because wrong Lens position ( due to wrong adapter focal flange) , then the FLE système get out of it's optimal position, then overcorrect or undercorrect ... Make it worst than not being corrected.

This would need to be tested, of course, but I doubt that the problem is as bad as you fear.

For one thing, you wouldn't be applying "minimum distance correction" at infinity. At worse you would apply something like "50m correction" at infinity, or "87cm correction" at 90cm.

What I wonder is: do we know if FLE correction ramps-up continuously throughout the whole focusing range, or if it only starts at near distances (like 1m) and increases as you get closer to minimum focus distance? The second scenario intuitively makes more sense to me, because the difference in correction between 2m and infinity must be minuscule.