Lens coding necessary? I think not.

[ramarren]

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On 12/10/2018 at 3:12 PM, pico said:

Lens coding necessary? I think not.

What advantage do our members find with lens coding? My view is that coding might help the post-processing initiate with wide-angle lenses, but not longer lenses. Any lens of 35mm  or longer do not need coding. Shorter lenses' coding offer promises but no significant advantage.

I'm an old Photoshop user by habit and practice and have employed its lens correction facility (which has regularly available updates in the application)  to no significant advantage.

The lens coding, and subsequently applied lens profiles, have several functions that pose some advantage for users. 

• The lens code informs the camera as to what lens is fitted, allowing the camera to read the associated lens profile and know the focal length and maximum aperture of the lens. This provides the camera more information with which to estimate the aperture in use for display and exposure purposes. For instance, the focal length information is used in evaluating when to start raising the ISO if you're using AutoISO. 
• The lens code automates selection of the lens profile, which saves time and reduces user errors. 
• The lens code and profile enable the lens information to be presented in EXIF data, which allows those who use tools that allow display of these camera attributes to use the information for various purposes. 
• Selection of a lens profile embeds the lens information into the metadata and applies lens correction information at the raw conversion level. Lens correction, in this instance, should be considered from Leica's unique take on lens correction ... My theory, based upon studying my lenses used on their original cameras and then on several different Leica digital cameras: 

Leica makes a huge effort to have their lenses image a particular way. When the medium is film and wet chemical processing and rendering, this is all you had to work with. With the advent of digital capture and digital image processing, there are both many more variations in how a lens can create an original capture and many more variations in how you can render it to a finished image. 

Leica's notion of the lens profile is to preserve the original intent and rendering of a lens into the raw capture independent of which digital body is used, and to help raw converters achieve the same desired look as the original intent at their default settings. They're not trying to correct all coma, all rectilinear distortion, etc as many other manufacturers do ... many of those aberrations are exactly what give Leica lenses their unique rendering look and are prized by photographer for those qualities. They're trying to have the intended rendering look of a lens stay the same regardless of which camera it's being used with. 

I've tested this theory by shooting the same scene with a particular Leica M or R lens using my film M  and R, and the M9, M-P, M-D, SL, and CL (over time, and not all at once...). With all but the M-D, I could turn off the lens profile and shoot un-profiled exposures as well. I've processed these and compared them. With the lens profiles on (barring a bad profile as appeared in a couple of the first SL lens profiles) what I see is that the digital cameras with lens profiles turned on produce a result with a very very high fidelity match to the original film images. The effect of using a lens profile is most pronounced when using short focal lengths, but I've seen small differences even with my Summicron-R 90mm and Elmar-R 180mm lenses. (There's a largish difference when I use the Macro-Elmarit-R 60mm with and a without the lens profile.)

That said, by and large the differences in rendering behavior become nuances and harder to see as focal length grows. As a practical matter, if you have a number of older lenses that aren't coded, if you use those lenses and do your corrections manually or using lens profile plug-ins later in the raw processor, you're not going to lose a lot. You'll still get good results, most of the time. 

Edited December 18, 2018 by ramarren

[mmradman]

1 hour ago, newnew said:

I also thought that when you send an older lens to Leica for coding they readjust it such that it works more precisely with the digital bodies. I recently got my Lux 75 coded and I am very happy with it.

 

Funny that.  Few years ago I bought secondhand Summilux 75 which was 6-bit coded, seller, a reputable uk shop never mentioned any recent service by Leica but coding was done to a factory standard similar to new M lenses.  It always focused spot on on my M cameras, MP, M9, M240 and M246 at all apertures I cared to use.  Having read countless posts about focus issues with this lens I can draw only two conclusions; 

I was very lucky (usual I am lucky with lens except on two occasion which were entirely my fault but insurance saved the day)

The lens may have been adjusted for use on digital RF camera at time 6-bit flange was fitted.

On that subject Merry Christmas all 🤗

[newnew]

Thanks. So your experience confirms that for some older lenses coding, when they change the lens mount, helps in quality.

[pico]

3 hours ago, jaeger said:

My experience of having the 6bit coding advantage is shutter/ISO coordination.  If not coded and shooting indoor or low light, having shutter and ISO speed on auto, while the minimal shutter speed is 1/focal length then BAM! 

I don't see where coding helps in this case.

 

[mmradman]

3 hours ago, pico said:

I don't see where coding helps in this case.

 

If using Auto ISO and aperture priority camera can be set to operate with minimum shutter speed as multiple of focal length.  To do that camera needs to know what lens if fitted, hence the 6-bit connection.  I have my m246 (same as m240) shutter speed set at 4*FL.

[pico]

33 minutes ago, mmradman said:

If using Auto ISO and aperture priority camera can be set to operate with minimum shutter speed as multiple of focal length.  To do that camera needs to know what lens if fitted, hence the 6-bit connection.  I have my m246 (same as m240) shutter speed set at 4*FL.

Of course if one is dependent upon Auto ISO, regardless, the lens or an adequate similar can be set manually or not at all. Setting properly merely requires the operator to know the basics of photography.

 

 

[lct]

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I begin to know a little bit about the basics of photography i believe but most of my pics are taken in manual + auto iso mode actually. Best invention since sliced bread if you ask me . Works fine with non-coded lenses but minimum shutter speed cannot be set as multiple of focal length with them. Not a bit deal to me me but my old hands are still steady fortunately. YMMV.

[mmradman]

35 minutes ago, pico said:

Of course if one is dependent upon Auto ISO, regardless, the lens or an adequate similar can be set manually or not at all. Setting properly merely requires the operator to know the basics of photography.

 

 

It is not question of depending but using the facility. Manual shutter and aperture priority are exposure options not Photographic dogmas.

[pico]

1 hour ago, mmradman said:

[...] Manual shutter and aperture priority are exposure options not Photographic dogmas.

What is the point here? Of course, we are free to exercise options other than accept auto exposure.

Edited December 19, 2018 by pico

[jaeger]

I just realized this topic has is already said "I think not".  I regret adding my opinion. 

[dugby]

On 12/11/2018 at 7:12 AM, pico said:

Lens coding necessary? I think not.

What advantage do our members find with lens coding? My view is that coding might help the post-processing initiate with wide-angle lenses, but not longer lenses. Any lens of 35mm  or longer do not need coding. Shorter lenses' coding offer promises but no significant advantage.

I'm an old Photoshop user by habit and practice and have employed its lens correction facility (which has regularly available updates in the application)  to no significant advantage.

You could test your theory by using one lens only, and taking the same shot over and over with manually selecting different lens codes from the camera menu