Summicron 50mm v4, 6-bit coding question.

[olegn]

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Hello, dear forum. I'm very close to buy a used 50mm cron v4 but i'm not sure if i understand correctely what means when there is no 6-bit coding on a lens. As far as i know there is a lens profile in a camera that corrects something (vignetting and what else) and the dng you get is more accurate. I have MM(1), M-D(262) and M10M. For the monochromes i think i can choose a lens pofile in a camera menu and it all be the same as if the lens has a 6-bit coding. What about the M-D? Am i right in total with what is going on with 6-bit coding? Thanks

[pippy]

Yes. You are correct.

I also have an M Monochrom, an M-D Typ-262 and a 50mm v4 Summicron and here, FWIW, are my views.

With the M Monochrom you should use the 11819 profile. With the M-D, of course, it isn't possible to do anything profile-wise.

To be perfectly honest I can't see any real-world difference using the lens on either body in terms of in-camera correction. I'm sure there will be some slight benefit at the corners but the Summicron is such a good performer that the lack of coding isn't an issue (for me). Regarding the M-D In the past I've tried out direct comparisons with uncorrected files and files corrected using the Summicron profile in Photoshop and couldn't see any real change at all so now I don't even give it a second thought.

If this lack of coding really bothers you then there are several ways - discussed elsewhere in the forum - to code the lens.

Just my viewpoint. I'm sure others will have a different approach.

P.

FWIW there ARE some lenses where the lack of coding makes a big difference when used with the M-D. These are mainly down at the wide-angle end of the focal-length world and the worst offenders are those lenses with a very deep-set rear element such as the 21mm f4 Super-Angulon. I've still not worked out how best to sort that one out...

Edited October 22, 2020 by pippy

[lct]

The 50/2 v4 can be coded by Leica if needed. It has the same code as the 50/2 v5 then (100001). Coding of the 50/2 v4 slightly corrects for distortion on the M240 but i have no experience with either M262 or M-D. FWIW.

Edited October 22, 2020 by lct

[Jean-Michel]

Go to: https://us.leica-camera.com/Photography/Leica-M/M-System-Service

There is a PDF there that you can download to see all the M lenses that can be coded by Leica

[pippy]

1 hour ago, lct said:

...Coding of the 50/2 v4 slightly corrects for distortion on the M240 but i have no experience with either M262 or M-D. FWIW...

I guess it will be pretty much the same for the M262 / M-D 262 as it is for the M240. Do they not share the same sensor?

If his numbers can be trusted our old mate Ken Rockwell gives the following figures for pincusion / barrel distortion correction in Ps;

Minimum focus : +0.4.

1m (3ft) : +0.4.

3m (10ft) : 0.0.

Infinity : -0.1.

Curious to see that his findings suggest a change from mild pincusion at 0.7m through neutral at 3m to near-invisible barrel-distortion at infinity. I wonder how the coding software can adjust for this change from one to the other if there's no way of the camera knowing focussing distance?

Anyhow; with a correction coefficient of between 0.0 and -0.1 for subject-matter from 3m to infinity that is something I can live with quite happily. If I ever do decide to shoot architectural subjects 3ft away I'll try to remember to sort them out in post............

Philip.

Edited October 22, 2020 by pippy

[lct]

45 minutes ago, pippy said:

Curious to see that his findings suggest a change from mild pincusion at 0.7m through neutral at 3m to near-invisible barrel-distortion at infinity. I wonder how the coding software can adjust for this change from one to the other if there's no way of the camera knowing focussing distance?

No idea but fact is there are slight differences between coded and uncoded pics re distortion. Hard to notice w/o doing side by side comparos though.

[pippy]

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5 minutes ago, lct said:

No idea but fact is there are slight differences between coded and uncoded pics re distortion. Hard to notice w/o doing side by side comparos though.

Yes, I agree completely.

I suppose the reason I had never noticed any difference myself is because I invariably shoot subject matter more than 2 to 3m away so if the distortion really is as slight as Rockwell suggests then with incredibly few exceptions - mainly architecture - it wouldn't be an issue for me. I can see how for users who habitually photograph right-up-close the +0.4 adjustment might be useful.

As I (usually remember to) set the lens profile with the M Monochrom the corrections will already be applied; it will only be when using the (screenless) M-D that any post-prod work might - under certain circumstances - be required.

Philip.