How can Leica not seeing it?

[250swb]

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Unfortunately I can distinguish a dirty sensor from banding. Yes my sensor is dirty and as I photograph these kind of subjects at around f11 that is even more visible, but that's not a big deal.

 

Have you ever wet cleaned this camera's sensor? No, I'm not telling you to clean it, but has a wet cleaning fluid left a clear film of some sort on the surface of the sensor?

[Giulio Zanni]

Have you ever wet cleaned this camera's sensor? No, I'm not telling you to clean it, but has a wet cleaning fluid left a clear film of some sort on the surface of the sensor?

 

 

Yes, I did wet cleaned the camera's sensor, so that could be a possibility, but I did the same with my other body which did not show this problem (the shutter got stuck half opened though and is now with Leica for repair).

[hoppyman]

With respect, it is impossible to reliably critique whatever is in your original DNG from the posted file. I saved and opened in a colour managed environment on a calibrated professional monitor which is using a workstation graphics card and operating in 30 bit. In the forum is a very low resolution 8 bit greyscale file. I can sample it as a perfectly smooth gradient in the sky from top to tree line.

[hoppyman]

The problem is much more visible in the Library module of LR which uses a narrower profile than in Develop which uses an RBG ProPhoto profile. The problem is that you export the image from Library. Like all the banding problems it diminishes by adding grain to the sky, the problem is that I want be able to add grain when it pleases me not just to get acceptable images. This is becoming a deal breaking for my kind of photography. I just want to make it working because I feel at home with Leica, but not to detriment of my images.

 I think that Lightroom operates in all modules in the same colour space which is similar to ProPhotoRGB, whatever your system may be able to reproduce. Only an exported version of the file may be in a different colour space.

Initially on import you will see the very low resolution 8 bit previews embedded in the DNG with the camera's embedded profile and then Lightroom generates better previews using what ever settings you chose.

If you want to add an effect selectively, you may like to experiment with the masking options to not apply that effect to smooth tones (like a clear sky)

[Giulio Zanni]

 I think that Lightroom operates in all modules in the same colour space which is similar to ProPhotoRGB, whatever your system may be able to reproduce. Only an exported version of the file may be in a different colour space.

Initially on import you will see the very low resolution 8 bit previews embedded in the DNG with the camera's embedded profile and then Lightroom generates better previews using what ever settings you chose.

If you want to add an effect selectively, you may like to experiment with the masking options to not apply that effect to smooth tones (like a clear sky)

 

 

No Lightroom uses different colour spaces between Library and Develop and and the most accurate preview is within Develop module at 1:1 or greater. It is documented all over the Adobe forums. In normal circumstances this would not affect the previews but if something is wrong in the chain it will show up. Usually I have to introduce grain on the sky to get rid of the problem but is something that I don't always want to do. Usually I also like dark dramatic skies, which enhances the problem even further. 

[hoppyman]

We have different understandings on Lightroom's colour spaces then. Perhaps a topic for a different forum.

It's a very complex subject. There are so many possible variables.

I agree that something wrong (or just different settings) in the chain can affect the results of course.
Perhaps you may like to comment on my remarks at #43?

I don't follow how anyone could reliably judge whatever is in your original DNG from that version.

However I think that some other forum members may be going to look at your DNG for you?
I hope that the discussion proves useful for everyone following

[Giulio Zanni]

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We have different understandings on Lightroom's colour spaces then. 

 

 

See this link from Adobe "How Lightroom Manages Colour": Lightroom uses Adobe RGB for previews in the Library, Map, Book, Slideshow, Print, and Web modules. In the Develop module, by default Lightroom displays previews using the ProPhoto RGB color space.

 

https://helpx.adobe.com/lightroom/help/color-management.html

[ralphh]

The problem is much more visible in the Library module of LR which uses a narrower profile than in Develop which uses an RBG ProPhoto profile. The problem is that you export the image from Library. Like all the banding problems it diminishes by adding grain to the sky, the problem is that I want be able to add grain when it pleases me not just to get acceptable images. This is becoming a deal breaking for my kind of photography. I just want to make it working because I feel at home with Leica, but not to detriment of my images.

 

That should not produce banding - quite the opposite in fact - as RGB is a narrower colour space, with the same number of tonal variations (16 bit), they are more subtle tone changes and therefor less banding. If LR produces more banding in Library, it's not because of RGB vs ProPhoto.  

 

I believe that LR displays its stored JPEG preview in library mode, and doesn't actually look at the DNGs (as demonstrated by the fact I can look at the library version of files on my external drive when it's unplugged.

 

But LR renders direct from the DNG in develop.  I would say that is more likely to blame as jpegs are always 8 bit -- you have an 8 bit preview in lib, and a 16 bit one in develop.

 

 

I'm using a calibrated Eizo, and I honestly can't see banding in either image, even if i take it to photoshop and increase the contrast and mess about with levels so much that the jpeg artifacts are obvious.  I can see a bit of a rainbow thing, which is actually not B&W, but purple which is kinda interesting.  I have to assume that's some wacky jpeg or processing artifact too as your camera is presumably incapable of outputting purple.

 

 A DNG would really help here as the jpeg artifacts are stronger than the effect you're trying to show us I think...

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[jaapv]

First let's get the terms clear here. The banding we are speaking  of here is posterization, 

The normal cause of posterization is insufficient bit depth in postprocessing. Which leads me to a quite different theory.

Obviously, due to added tolerances in components no two cameras will expose exactly the same. it may well be that setting EV comp. to +1/3rd on the culpable camera solves the problem completely.

[Guest]

Just a quick question ... are you using any of the LR present auto lens corrections for Leica lenses ... a known issue was a banding like the one you describe ... disappears when you turn off the auto correction. 

 

Bob

[Giulio Zanni]

Just a quick question ... are you using any of the LR present auto lens corrections for Leica lenses ... a known issue was a banding like the one you describe ... disappears when you turn off the auto correction. 

 

Bob

 

 

I generally use auto lens correction but after the files are imported and the problem is already there.

[Giulio Zanni]

That should not produce banding - quite the opposite in fact - as RGB is a narrower colour space, with the same number of tonal variations (16 bit), they are more subtle tone changes and therefor less banding. If LR produces more banding in Library, it's not because of RGB vs ProPhoto.  

 

 

A narrower space produce more compression. In general I see much more tones and subtle colours/transitions in Photoshop and in Develop than in the previews of Library. The problem about Lightroom often producing different looks between Library and Develop is well documented all over the web. I know many pros that use bridge to avoid this problem. 

 

Just as an example http://photo.net/digital-darkroom-forum/00dYOv

 

You are right about the purple. What I see are concentric circles, a sort of rainbow effect, with some magenta here and there.

[ralphh]

Oh I agree that LR is different in lib and dev modes, but I think it's because they run 8 and 16 but respectively as library is jpeg based.

 

In fact, in that thread you linked, someone mentions that library uses 8 but jpegs

 

 

Arguments about precisely why LR sucks aside, are we getting a DNG to play with?

[Giulio Zanni]

Oh I agree that LR is different in lib and dev modes, but I think it's because they run 8 and 16 but respectively as library is jpeg based.

 

In fact, in that thread you linked, someone mentions that library uses 8 but jpegs

 

 

Arguments about precisely why LR sucks aside, are we getting a DNG to play with?

 

 

I sent DNGs to Jaap, who has looked at them, if you send me in PM your e-mail address I will send you DNGs via wetransfer

[mjh]

A narrower space produce more compression.

A narrower colour space allows for finer distinctions between colours and thus lessens the risk of banding/posterisation – assuming the bit depth is the same. A different bit depth can make a difference of course and there may be posterisation in an 8 bit format that isn’t visible with 16 bits, but the colour space has no bearing on that effect.