M11 + 35mm Summilux FLE - wide open (f1.4) + infinity focus - Expectation on focus point

[hmzimelka]

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12 hours ago, Jewl said:

I have the perception this is something with the M11 bodies. As you know, had the same experience which needed to be corrected twice. Maybe there is a calibration of the body and 35mm lux fle required even if they are new?!

More a Leica quality assurance and consistency thing with the lenses than a M11 specific thing.

It's very likely the 35/1.4 has some minor focus shift that can't be corrected for by the FLE system or lens design, and that Leica optimises focus for f/2 or something. This is just a guess and no justification or excuse for Leica to not calibrate hard infinity stop properly. The FLE system is mostly there to optimise contrast and sharpness at different focus distances by managing spherical aberrations than eliminate focus shift. Focus shift, the way I understand it, stems from a lens design where the lens has an effectively different focal length for light traveling through the periphery of the lens versus the light traveling more head and perpendicular... hence stopping down changes the light path more down the centre and thus moving the focus further away. Like changing focus can change focal length of some lenses and/or the effective speed or light transmission of a lens, which is something more prevalent with macro and micro lenses.

The focus shift of the 35/1.4 FLE would be almost imperceptible on a M10. On the M11 it was not enough to loose good contrast but enough to loose fine detail on the M11.

The new Summicron 35 ASPH II I bought last year had a HUGE amount of focus shift and I returned it. That and a slightly blurry right edge. The lens was clearly a lemon.

My experience with the Voigtlander QC lottery (as I've heard it being called) is far better in terms of getting a perfect lens than with Leica. It's a pity, as Leica just nails the industrial design and haptics of their lenses. But my bank account and wife are probably very grateful that I haven't purchased the Leica glass. Especially in light with how fantastic the Ultron 28mm ASPH II is. 

Anyways, I'm off to enjoy the rest of my short stay in Cape Town. No camera stores and lens testing anymore. My recent experience with the 35/1.4 and 75/2 has cured my Leica GAS, at least for a while.

Edited August 21, 2022 by hmzimelka

[lct]

4 hours ago, hmzimelka said:

The focus shift of the 35/1.4 FLE would be almost imperceptible on a M10. On the M11 it was not enough to loose good contrast but enough to loose fine detail on the M11.

Not sure i would generalize this way with respect. I've noticed no significant focus shift on my 24mp M240 and 42mp A7r2 mod either so i would be surprised it is much different on the 60mp M11. 

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[Photoworks]

18 hours ago, hmzimelka said:

The focus shift of the 35/1.4 FLE would be almost imperceptible on a M10. On the M11 it was not enough to loose good contrast but enough to loose fine detail on the M11.

 

where is this coming from, I use the 35 FLE 80% of the time, M10P M10R and now M11

spot on focusing. and I shoot mostly a 1.4

[hmzimelka]

5 hours ago, Photoworks said:

where is this coming from, I use the 35 FLE 80% of the time, M10P M10R and now M11

spot on focusing. and I shoot mostly a 1.4

Then it must be copy variance on the lens. The copy I tried had focus shift. I'm not claiming all 35/1.4 ASPH FLE lenses have focus shift. 

[lct]

3 hours ago, hmzimelka said:

Then it must be copy variance on the lens. The copy I tried had focus shift. I'm not claiming all 35/1.4 ASPH FLE lenses have focus shift. 

Are you sure you did not take back or front focus for focus shift? Just did a boring test at 60mp and found zero focus shift at all apertures as expected.

[hmzimelka]

2 hours ago, lct said:

Are you sure you did not take back or front focus for focus shift? Just did a boring test at 60mp and found zero focus shift at all apertures as expected.

Yes. I know what focus shift is

 

[lct]

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7 hours ago, hmzimelka said:

Yes. I know what focus shift is

OK thanks then it is a mystery for me. Sample variation is something i can understand on earlier lenses like Summicron 35/2 asph v1 designed in the nineties with copies calibrated either for film or digital but the Summilux 35/1.4 FLE is a later lens from 2010 whose copies are all 6-bit coded and calibrated for digital. Redid my test at 1m subject distance (previous one was at 5m) with the same perfect result at all apertures so to me it is a lens that is not prone to focus shift at any resolution.