Voigtländer lens coding

[Crem]

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I’m a new Leica M user so sorry if this is common info. Currently I use Leica lenses, but I’m thinking of trying some of the Voigtländers. I’m having difficulty finding info on manual 6 bit coding:

1. Does the manual coding effect the raw files or only jpegs?

2. What corrections get applied? I’ve read everything from color tint, to vignette, to distortion.

3. Does anyone know of a website that maintains a list of all the 3rd party lenses and the recommended 6 bit coding?

4. Should I skip manually coding and instead use the correct lens profiles in Lightroom?

Thank you for you help!

 

 

 

 

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[adan]

Not sure you are asking all the right questions - but I'll answer as best I can.

1. The coding, whether manual or built-in at the Leica factory, will affect both jpegs and raw files more or less equally. It affects the camera programming enroute between the sensor and the final file on the SD card.

2. The coding only automatically corrects, in the camera, for color vignetting and normal brightness vignetting (to a variable extent).*

In addition, the fact that the lens type is then also recorded in a picture's EXIF metadata means that, after the fact, depending on what post-processing software one uses, the post-processing software (not the camera) may apply corrections for distortion and some regular vignetting.

I have coded lenses, I use Photoshop CS6 and Adobe Camera Raw. They do absolutely nothing to fix distortion or vignetting just because the lens is coded. Those still have to be manually corrected with sliders, coding or not. Other software may vary, and may have an "on/off" switch to automatically detect the lens type and apply corrections, or not - see post-processing software instructions

3. This site has a list of the 6-bit codes - not sure how up-to-date: https://lavidaleica.com/content/leica-lens-codes

The L-Camera Forum used to, but right now our link is reading "404." I've reported it - the mods may repair it. See top of the M Lenses subforum for the thread with the link.

4. Lightroom (or other) profiles will do zip/nada/nothing to fix the color vignetting problem, when it exists. It has to be done in-camera at the moment of exposure for decent (and fast, automatic, seamless) results. I think Lightroom now has a "flat-field" plug-in that can help - but it stills requires some user intervention. Not as seamless as getting it fixed at the moment of exposure, all the time, every picture.

Only 1) coding the lens, or 2) using the camera's lens menu to identify the lens type in use, will fix the color vignetting automatically and easily.

___________________

*The deal is this. Digital sensors do not play nicely with old-fashioned, rangefinder-type, close-to-the-sensor, wide-angle lenses (35mm or wider). This produces both brightness vignetting (closer and closer to the picture corners, not all the light gets to the silicon), and color vignetting (the light sometimes leaks from a red- or blue-filtered pixel onto a green-sensitive pixel (or vice-versa), and gets recorded as the wrong color).

Lenses longer than 50mm usually do not show any vignetting problems if uncoded - they sit far enough away from the image plane/sensor.

In the second case, this causes a measurable stain of magenta or blue-green along the short "sides" of the image and in the corners. A.K.A. "Italian Flag syndrome." See photograph below.

See diagram of older sensors (left), and the newer Leica CMOS sensors with different construction at the pixel level, which correct things partially. But not for all wide lenses - I can still see obvious problems with 35 and 28 images even on the M10 with the improved sensor, if the lenses are not coded, or ID'd via the lens menu.

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

The Leica M color cameras have corrections built into their firmware to dial out both types of vignetting, if the camera "knows" exactly which lens was used. It adds or subtracts color from parts of the image right-now after exposure, while the image data is being processed in-camera enroute to the SD card.

This shows what color vignetting looks like - pink stain on the left, cyan on the right (like an Italian flag: 1980 Leica 21mm Elmarit, with "poor" correction from early M9 firmware, 2010).

Lenses' vignetting patterns are like fingerprints - they depend on the precise path the light takes passing through the particular shapes of glass in the optical layout. All 35mm f/2 Summicron ASPH lenses behave about the same, but not all 35mm f/2 lenses overall necessarily act the same. 35 Summicron v.4 non-ASPH needs different corrections than 35 Summicron ASPH, which needs different corrections (maybe) than a Voigtlander 35mm Ultron. Leica supplies different 6-bit codes for different 35mm f/2 Summicron lens designs (1980 vs. 1997, for example).

Do not assume that any 21, or 24, or 28, or 35 coding will necessarily work with just anyone's lens of the same speed and focal length.

However, some designs are similar enough - even from different manufacturers and eras, that they can work for each other. For example, the corrections for the Leica 35mm Summicron v.4 (1980) work quite well for the Voigtlander 35mm f/1.4 Nokton v.1/2 - because they are similar, compact Double-Gauss designs.

The reason I said the vignetting corrections are "variable" is that they are applied less strongly at higher ISOs, to prevent the corrected corners/edges getting too noisy.

 

Edited April 10, 2021 by adan

[Guest]

3 hours ago, adan said:

Not sure you are asking all the right questions - but I'll answer as best I can.

1. The coding, whether manual or built-in at the Leica factory, will affect both jpegs and raw files more or less equally. It affects the camera programming enroute between the sensor and the final file on the SD card.

2. The coding only automatically corrects, in the camera, for color vignetting and normal brightness vignetting (to a variable extent).*

In addition, the fact that the lens type is then also recorded in a picture's EXIF metadata means that, after the fact, depending on what post-processing software one uses, the post-processing software (not the camera) may apply corrections for distortion and some regular vignetting.

I have coded lenses, I use Photoshop CS6 and Adobe Camera Raw. They do absolutely nothing to fix distortion or vignetting just because the lens is coded. Those still have to be manually corrected with sliders, coding or not. Other software may vary, and may have an "on/off" switch to automatically detect the lens type and apply corrections, or not - see post-processing software instructions

3. This site has a list of the 6-bit codes - not sure how up-to-date: https://lavidaleica.com/content/leica-lens-codes

The L-Camera Forum used to, but right now our link is reading "404." I've reported it - the mods may repair it. See top of the M Lenses subforum for the thread with the link.

4. Lightroom (or other) profiles will do zip/nada/nothing to fix the color vignetting problem, when it exists. It has to be done in-camera at the moment of exposure for decent (and fast, automatic, seamless) results. I think Lightroom now has a "flat-field" plug-in that can help - but it stills requires some user intervention. Not as seamless as getting it fixed at the moment of exposure, all the time, every picture.

Only 1) coding the lens, or 2) using the camera's lens menu to identify the lens type in use, will fix the color vignetting automatically and easily.

___________________

*The deal is this. Digital sensors do not play nicely with old-fashioned, rangefinder-type, close-to-the-sensor, wide-angle lenses (35mm or wider). This produces both brightness vignetting (closer and closer to the picture corners, not all the light gets to the silicon), and color vignetting (the light sometimes leaks from a red- or blue-filtered pixel onto a green-sensitive pixel (or vice-versa), and gets recorded as the wrong color).

Lenses longer than 50mm usually do not show any vignetting problems if uncoded - they sit far enough away from the image plane/sensor.

In the second case, this causes a measurable stain of magenta or blue-green along the short "sides" of the image and in the corners. A.K.A. "Italian Flag syndrome." See photograph below.

See diagram of older sensors (left), and the newer Leica CMOS sensors with different construction at the pixel level, which correct things partially. But not for all wide lenses - I can still see obvious problems with 35 and 28 images even on the M10 with the improved sensor, if the lenses are not coded, or ID'd via the lens menu.

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

The Leica M color cameras have corrections built into their firmware to dial out both types of vignetting, if the camera "knows" exactly which lens was used. It adds or subtracts color from parts of the image right-now after exposure, while the image data is being processed in-camera enroute to the SD card.

This shows what color vignetting looks like - pink stain on the left, cyan on the right (like an Italian flag: 1980 Leica 21mm Elmarit, with "poor" correction from early M9 firmware, 2010).

Lenses' vignetting patterns are like fingerprints - they depend on the precise path the light takes passing through the particular shapes of glass in the optical layout. All 35mm f/2 Summicron ASPH lenses behave about the same, but not all 35mm f/2 lenses overall necessarily act the same. 35 Summicron v.4 non-ASPH needs different corrections than 35 Summicron ASPH, which needs different corrections (maybe) than a Voigtlander 35mm Ultron. Leica supplies different 6-bit codes for different 35mm f/2 Summicron lens designs (1980 vs. 1997, for example).

Do not assume that any 21, or 24, or 28, or 35 coding will necessarily work with just anyone's lens of the same speed and focal length.

However, some designs are similar enough - even from different manufacturers and eras, that they can work for each other. For example, the corrections for the Leica 35mm Summicron v.4 (1980) work quite well for the Voigtlander 35mm f/1.4 Nokton v.1/2 - because they are similar, compact Double-Gauss designs.

The reason I said the vignetting corrections are "variable" is that they are applied less strongly at higher ISOs, to prevent the corrected corners/edges getting too noisy.

 

Must admit i coded my voigtlander 40mm f1.4 as a 35mm summilux pre-asph,,,do you think that is a sensible selection?

I went fot that code because i read the lens was based on the early summilux.

[Crem]

7 hours ago, adan said:

Not sure you are asking all the right questions - but I'll answer as best I can.

1. The coding, whether manual or built-in at the Leica factory, will affect both jpegs and raw files more or less equally. It affects the camera programming enroute between the sensor and the final file on the SD card.

2. The coding only automatically corrects, in the camera, for color vignetting and normal brightness vignetting (to a variable extent).*

In addition, the fact that the lens type is then also recorded in a picture's EXIF metadata means that, after the fact, depending on what post-processing software one uses, the post-processing software (not the camera) may apply corrections for distortion and some regular vignetting.

I have coded lenses, I use Photoshop CS6 and Adobe Camera Raw. They do absolutely nothing to fix distortion or vignetting just because the lens is coded. Those still have to be manually corrected with sliders, coding or not. Other software may vary, and may have an "on/off" switch to automatically detect the lens type and apply corrections, or not - see post-processing software instructions

3. This site has a list of the 6-bit codes - not sure how up-to-date: https://lavidaleica.com/content/leica-lens-codes

The L-Camera Forum used to, but right now our link is reading "404." I've reported it - the mods may repair it. See top of the M Lenses subforum for the thread with the link.

4. Lightroom (or other) profiles will do zip/nada/nothing to fix the color vignetting problem, when it exists. It has to be done in-camera at the moment of exposure for decent (and fast, automatic, seamless) results. I think Lightroom now has a "flat-field" plug-in that can help - but it stills requires some user intervention. Not as seamless as getting it fixed at the moment of exposure, all the time, every picture.

Only 1) coding the lens, or 2) using the camera's lens menu to identify the lens type in use, will fix the color vignetting automatically and easily.

___________________

*The deal is this. Digital sensors do not play nicely with old-fashioned, rangefinder-type, close-to-the-sensor, wide-angle lenses (35mm or wider). This produces both brightness vignetting (closer and closer to the picture corners, not all the light gets to the silicon), and color vignetting (the light sometimes leaks from a red- or blue-filtered pixel onto a green-sensitive pixel (or vice-versa), and gets recorded as the wrong color).

Lenses longer than 50mm usually do not show any vignetting problems if uncoded - they sit far enough away from the image plane/sensor.

In the second case, this causes a measurable stain of magenta or blue-green along the short "sides" of the image and in the corners. A.K.A. "Italian Flag syndrome." See photograph below.

See diagram of older sensors (left), and the newer Leica CMOS sensors with different construction at the pixel level, which correct things partially. But not for all wide lenses - I can still see obvious problems with 35 and 28 images even on the M10 with the improved sensor, if the lenses are not coded, or ID'd via the lens menu.

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

The Leica M color cameras have corrections built into their firmware to dial out both types of vignetting, if the camera "knows" exactly which lens was used. It adds or subtracts color from parts of the image right-now after exposure, while the image data is being processed in-camera enroute to the SD card.

This shows what color vignetting looks like - pink stain on the left, cyan on the right (like an Italian flag: 1980 Leica 21mm Elmarit, with "poor" correction from early M9 firmware, 2010).

Lenses' vignetting patterns are like fingerprints - they depend on the precise path the light takes passing through the particular shapes of glass in the optical layout. All 35mm f/2 Summicron ASPH lenses behave about the same, but not all 35mm f/2 lenses overall necessarily act the same. 35 Summicron v.4 non-ASPH needs different corrections than 35 Summicron ASPH, which needs different corrections (maybe) than a Voigtlander 35mm Ultron. Leica supplies different 6-bit codes for different 35mm f/2 Summicron lens designs (1980 vs. 1997, for example).

Do not assume that any 21, or 24, or 28, or 35 coding will necessarily work with just anyone's lens of the same speed and focal length.

However, some designs are similar enough - even from different manufacturers and eras, that they can work for each other. For example, the corrections for the Leica 35mm Summicron v.4 (1980) work quite well for the Voigtlander 35mm f/1.4 Nokton v.1/2 - because they are similar, compact Double-Gauss designs.

The reason I said the vignetting corrections are "variable" is that they are applied less strongly at higher ISOs, to prevent the corrected corners/edges getting too noisy.

 

adan, fantastic info and thank you for taking the time to write it up! It makes much more sense the way you explained it vs the random bits of info I found with Google searches. 

[adan]

5 hours ago, steve 1959 said:

Must admit i coded my voigtlander 40mm f1.4 as a 35mm summilux pre-asph,,,do you think that is a sensible selection?

I went fot that code because i read the lens was based on the early summilux.

Probably an adequate choice. Not that much difference between those lenses.

Especially with real-world pictures. What is an obvious color stain with snow or a white wall quickly gets "camouflaged" in a regular picture with a mish-mosh of textures and colors all over the frame.