50mm Summilux pre-ASPH focus shift

[evikne]

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I have discovered some focus shift on my 50mm Summilux pre-ASPH v3. The focus is pretty accurate at f/1.4, but it wanders backwards as I stop down to f/2 and further. I often use the lens at f/2 because the colors and sharpness is better here. A little test reveals that f/2 is actually where the lens is at its best, at least for portraits, because stopped further down the back focus makes the focused point more unsharp, even though the DOF is increased.

I assume there is not much to do with the focus shift, but I want to have my lens 6-bit coded, and I wonder if it might be a good idea to have the lens calibrated for f/2 instead of f/1.4 at the same time, to get the very best out of the lens at this aperture. The focus shift will probably also be a little better at f/2.8 and further down.

What do you think? Does it sound reasonable to do so? And does anyone know if the 50 Summicron v5 is noticeably sharper at f/2 than the 50 Summilux v3 at the same aperture? Whatever the answer is, I still think the Summilux is more versatile, because I have the possibility for f/1.4 when I want it, exactly like my 35 Summilux pre-ASPH v2.

[a.noctilux]

Yes, I see that for decades.

After using a while (some years), in film days, it was not so visible in slides 😊.

 

In digital days, I learn to live with those "flaws = characters", trying not to worry in most cases.

In digital, if possible, I try with focus brackettings (millimeter turnings of the focus ring).

In real life use, I just avoid f/2 to f/4 on my Noctilux 1.0 and Summilux 50mm.

I consider them as f/1 (1.4) or f/5.6 onward 😇.