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Thread: Compressed VS Uncompressed DNGs - A quick test

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    Lightbulb Compressed VS Uncompressed DNGs - A quick test

    Hi guys,

    I finally had time to do some testing and would like to share my results with you. It is about something that has always kept me wondering since first testing an M9: Is there a difference between shooting compressed or uncompressed raw files with the Leica M9? And if yes, how significiant is it? After all file size is twice as large and this is something for me to consider.
    The first thing I did, when I received my camera in June of this year was to set it to uncompressed capture mode as I'm always aiming for the highest IQ possible. Logic says (at least mine does) that the words "lossless" and "compression" don't add up too well.

    So what I tried to achieve in this test was to determine how severe an adjustment had to be, in order to show a negative effect on image quality and whether it shows earlier in the compressed raw file. Please note: These adjustments are beyond all reason and a sane person would probably never adjust that much. I personally try to do as little PP as necessary but it's a test after all, so please put on your color muting protective goggles!
    What you could say is that I basically tried to destroy the files through postprocessing...


    The first image of each set was shot in uncompressed mode and the second one was in compressed mode. The first set was overexposed just enough for LR to show a highlight clipping warning.
    This is what the files looked like right out of the camera:



    And this is what they looked liked after these adjustments to the right. I boosted vibrance and saturation to try to cause banding in the sky...



    Here are some 100% crops side by side:








    Next I did the exact same thing with an increadibly underexposed file.
    Before:



    And after this processing-torture:



    100% view:




    Even though I did this test with an M9 the same might apply to the new M aswell.


    So in the end what does this tell us? Well, to me it is very confusing that there doesn't seem to be the slightest difference between compressed and uncompressed raw files.
    What am I missing here? I would at least have expected some banding issues in the sky, more noise, artifacts whatever. Or is it just my screen that isn't capable of displaying the horrible differences?

    On the bright side it shows what a great camera the M9 still is.



    What do you think?

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    http://maxkissler.com/
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    Re: Compressed VS Uncompressed DNGs - A quick test

    By and large, you're right - there is no difference. It's a mostly lossless compression.

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    Re: Compressed VS Uncompressed DNGs - A quick test

    Photographers are weird. Over at the Sony section, many are demanding uncompressed RAWs and how the compressed RAWs "crunch" their images at the pixel level and yet here you are enjoying compressed RAW.

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    Re: Compressed VS Uncompressed DNGs - A quick test

    I guess it depends on whether the compression is lossy or not, even if they say is it lossless.

    I can't see the difference with my S2, which is lossless compression DNGs, but that camera's bit rate is higher than most. The M9 is also lossless DNG files.

    I wonder if it is different with other RAW file formats when PPed in Adobe software?

    (I'm out of my geek-depth here, so take it all with a grain of salt).

    - Marc
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    Re: Compressed VS Uncompressed DNGs - A quick test

    I was under the impression the M9 was not lossless but the newer M is.
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    Re: Compressed VS Uncompressed DNGs - A quick test

    Quote Originally Posted by Duane Pandorf View Post
    I was under the impression the M9 was not lossless but the newer M is.
    You are correct.
    The M9 has indeed lossy compression.
    The M240 has lossless compression.

    The algorithm used in the M9 throws practically speaking away bits at the noise level. I think I have seen only one carefully crafted example where one could see a difference when pixel peeping.

    Of course one can take an M9 uncompressed file and compress it with Adobe software in lossless fashion.
    With best regards, K-H.
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    Re: Compressed VS Uncompressed DNGs - A quick test

    Lossless or not: It's good enough for my taste. So I'll probably change my settings to compressed mode now. Usually I don't over- or underexpose by more than a stop so it won't make much of a difference I guess.

    Btw, I get consistent results when using higher ISO speeds and even when I push underexposed high-ISO files I don't see any difference in the amount or character of noise.
    http://maxkissler.com/
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    Re: Compressed VS Uncompressed DNGs - A quick test

    You may want to have a look at this thread. M9 Colors at Night

    Good luck.
    With best regards, K-H.

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    Re: Compressed VS Uncompressed DNGs - A quick test

    You are thinking your eye is really good at seeing luminance difference. The reason 8-bit image files are standard is that for the eye to perceive a stepless gradient from black to white, the gradient needs approximately 200 levels of gray. So when you have an image starting with so much more, you really need to push it to see it break down.

    The other problem is I can actually have far fewer than 200 levels of gray to reproduce a "photographic" image. The more detail and the shorter the gradient, the less I need.

    The idea of "the more the better" might be true, it might not be perceived either. And if you cannot see the difference in a photograph, is it really different?

    On an associated note, many photographers default to ProPhotoRGB because it is a large gamut. What they don't understand is you don't actually get more discrete colors because of the gamut size--what you get is coarser color gradients and a whole bunch of empty registers (in the case of ProPhoto). Going to ProPhotoRGB actually reduces the number of discrete colors in a file which is why it needs to be 16-bit in order to simply not band. If you don't believe me, take an AdobeRGB image and convert it to ProPhotoRGB and watch the area of the histogram compress. Bigger is not always better.

    Now, about this fixation about the number of pixels...

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    Re: Compressed VS Uncompressed DNGs - A quick test

    Shashin, couldn't you sum all you said by saying "Less is More"?

    All kidding aside, I'm appreciative this test was performed as I often wondered about the M9 lossy compression. If these tests indicate anything, it's that the compression algorithms used are extremely fine. I've seen other examples of high quality lossy vs. loseless compression in other cameras and there often is a world of difference.

    Dave (D&A)
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    Re: Compressed VS Uncompressed DNGs - A quick test

    Quote Originally Posted by Shashin View Post
    ...

    On an associated note, many photographers default to ProPhotoRGB because it is a large gamut. What they don't understand is you don't actually get more discrete colors because of the gamut size--what you get is coarser color gradients and a whole bunch of empty registers (in the case of ProPhoto). Going to ProPhotoRGB actually reduces the number of discrete colors in a file which is why it needs to be 16-bit in order to simply not band. If you don't believe me, take an AdobeRGB image and convert it to ProPhotoRGB and watch the area of the histogram compress. Bigger is not always better.
    ...
    Maybe I misread what you were saying but I don't understand why anyone would do this?

    I personally use ProPhotoRGB because I know (or am quite certain) that my cameras deliver files that have a large enough color gamut for ProPhotoRGB to make sense. Though I admit, it doesn't make much of a difference to using Adobe RGB. Before printing, the files get translated to the according color spaces anyway which happen to be a lot smaller than any of the former ones.

    Sadly, none of this is making me take better images...

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    Re: Compressed VS Uncompressed DNGs - A quick test

    BTW, I exported the first two images as 16bit tiffs and processed a little more aka "made completely senseless adjustments" that should have produced a difference between the compressed and uncompressed image, viewed them side by side on one of my school's Eizo screens and didn't see a difference. As I've previously said, from now on compressed mode it is....

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    Re: Compressed VS Uncompressed DNGs - A quick test

    Max, if you use an unnecessarily large gamut like ProPhotoRGB, you can simply be throwing away data. I never simply default to that unless it is clear AdobeRGB is not large enough. I have yet to find AdobeRGB too small for what I shoot. Also, if you are letting your CM system simply rescale one gamut into another, then you are also transforming the image. Another reason I like AbobeRGB as it is closer to the print space.
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    Re: Compressed VS Uncompressed DNGs - A quick test

    Well, forward looking to better software and better displays doesn't it make sense to use ProPhotoRGB and 16 bits?
    With best regards, K-H.
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    Re: Compressed VS Uncompressed DNGs - A quick test

    Quote Originally Posted by Shashin View Post
    Max, if you use an unnecessarily large gamut like ProPhotoRGB, you can simply be throwing away data. I never simply default to that unless it is clear AdobeRGB is not large enough. I have yet to find AdobeRGB too small for what I shoot. Also, if you are letting your CM system simply rescale one gamut into another, then you are also transforming the image. Another reason I like AbobeRGB as it is closer to the print space.
    Good point Will.


    Though I feel using a perceptive rendering intent is usually getting me very close to what I want / previously saw.
    Last edited by MaxKi▀ler; 10th December 2013 at 15:19.

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    Re: Compressed VS Uncompressed DNGs - A quick test

    Max, just as your post is really alluding to, it is about the results. There are so many variables in a photograph, to to mention the big variable of the photographer's taste, that is really hard to make hard and fast rules. I have stopped sweating the small stuff long ago. It is good to know because sometimes it does make a difference.
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    Re: Compressed VS Uncompressed DNGs - A quick test

    Quote Originally Posted by k-hawinkler View Post
    Well, forward looking to better software and better displays doesn't it make sense to use ProPhotoRGB and 16 bits?
    16-bit is always worth using. Why lose data by going to 8-bit?

    ProPhotoRGB might be worth using depending on the gamut of your image. AdobeRGB will be better and retain more detail if the image falls into that gamut. A particular color space does not make the image "better" as long as nothing goes out of gamut. You can maximize your data if you can closely match your image to a particular gamut.

    Also, as far as choices for bit depth and color space, it has a lot to do with the ability to process the image rather than the image "looking better." You will not see the difference between a perfect 8-bit or 16-bit image.
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    Re: Compressed VS Uncompressed DNGs - A quick test

    Thanks. Processing the image as good as possible is my main concern.
    I am also finding going back to old RAW files and processing anew gives me better results.
    Partially through improved software and partially because I learned a thing or two.
    With best regards, K-H.
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    Re: Compressed VS Uncompressed DNGs - A quick test

    For me the images on the right are softer(less crispness in details) & mushy in comparison, but then I am no expert.
    I also use the M9 and as I don't shoot thousands and rapid shoot etc. the file size is not an issue, you can dedicate extra disks for storage at today's prices.

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    Re: Compressed VS Uncompressed DNGs - A quick test

    Quote Originally Posted by ced View Post
    For me the images on the right are softer(less crispness in details) & mushy in comparison, but then I am no expert.
    I also use the M9 and as I don't shoot thousands and rapid shoot etc. the file size is not an issue, you can dedicate extra disks for storage at today's prices.
    Maybe you either see it because you want to see it or because the windows snipping tool is compromising image quality. What if I didn't write which is which or if I now told you I switched it on purpose?

    Perhabs I should have mentioned that it was very windy so there might be some motion blur in it.

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    Re: Compressed VS Uncompressed DNGs - A quick test

    Thank you for this interesting discussion.
    I have always chosen not to compress files: partly because I have been concerned that there may be some loss of information from the files; and partly because I have been concerned that as time goes on, and software evolves, it may become harder to decompress/read those files. I am not a software wizard and could be quite wrong, but it just seems a bit safer.
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    Re: Compressed VS Uncompressed DNGs - A quick test

    Compression etc:
    There are all sorts of compression schemes, some are lossy, some are not.
    zip compression, for example, is loss-less. Imagine what would happen if random bits suddenly changed in the software you just downloaded.
    jpeg compression, is usually lossy, although there is a loss-less variant in the jpeg2000 standard.

    In general, lossy compression achieves smaller files however what we want as photographers is to have "perfect" images and maximum storage card capacity.

    Sometimes selection of one or the other is a balance between card capacity and write-time. Depending on the relative write speed of the card/camera with the time it takes to compress the image, the rate at which images are stored are sometimes slowed by compression, OTOH, for most current cameras it may actually be improved.

    My test for lossless compression is to always compare what would the bits be if compressed vs un-compressed. All true lossless compression schemes will yield the exact same result, although the path to that result may be different.

    I once tested Nikon's lossless compression and found that to be true..
    I have no reservation about using lossless compression other than the usual unpredictable result on the display of remaining card capacity. With lossless compressed files, the number of images remaining is usually understated.
    -bob
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    Re: Compressed VS Uncompressed DNGs - A quick test

    Just wanted to let you know: The M9 (and I guess the same applies to other M cameras) uses indeed lossless compression. My local Leica dealer confirmed this today. The option to shoot uncompressed is to maximize compatibility with several raw developers that cannot open compressed raw files. So if you're using software that can open compressed raws you don't need to worry.

    Cons:
    Camera takes slightly longer to write to card.
    Is it future-proof?

    Pros:
    Shorter import times / Backing up files on an external HD is also faster.
    Pretty obvious, almost twice as many images go on one sd card.

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    Re: Compressed VS Uncompressed DNGs - A quick test

    Quote Originally Posted by MaxKi▀ler View Post
    Though I admit, it doesn't make much of a difference to using Adobe RGB. Before printing, the files get translated to the according color spaces anyway which happen to be a lot smaller than any of the former ones.
    Inkjet printers like the popular Epson 3880 definitely have gamut with colors that extend beyond AdobeRGB. In the diagram below, the color polygon is AdobeRGB and the white is a printer profile for luster paper for 3880. There are printers with even larger gamut so it makes sense to use color spaces larger than AdobeRGB.

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    Re: Compressed VS Uncompressed DNGs - A quick test

    Quote Originally Posted by Shashin View Post
    Max, if you use an unnecessarily large gamut like ProPhotoRGB, you can simply be throwing away data. I never simply default to that unless it is clear AdobeRGB is not large enough. I have yet to find AdobeRGB too small for what I shoot. Also, if you are letting your CM system simply rescale one gamut into another, then you are also transforming the image. Another reason I like AbobeRGB as it is closer to the print space.
    Is the AdobeRGB really big enough for you? The following diagrams show pixels from a picture of an ordinary tree with green leaves plotted into the CIE chromaticity "horseshoe". The three triangles are gamuts of sRGB, AdobeRGB and ProPhoto RGB. One diagram is exported as ProPhoto and one as AdobeRGB. As you can see, lots of the greens had to be remapped from its original color to fit inside AdobeRGB. So using AdobeRGB meant in this particular case throwing away data - something that you apparently like to avoid...



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    Re: Compressed VS Uncompressed DNGs - A quick test

    Quote Originally Posted by MaxKi▀ler View Post
    Just wanted to let you know: The M9 (and I guess the same applies to other M cameras) uses indeed lossless compression. My local Leica dealer confirmed this today.
    Your shots look like there is no difference. But document on a Leica site says "choice of uncompressed or slightly compressed (by non-linear reduction of color depth)" - go to Leica Camera AG - Photography - M9 & M9-P and click on the Technical Data link. Non linear reduction of color depth means lossy.
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    Re: Compressed VS Uncompressed DNGs - A quick test

    Quote Originally Posted by MirekE View Post
    Your shots look like there is no difference. But document on a Leica site says "choice of uncompressed or slightly compressed (by non-linear reduction of color depth)" - go to Leica Camera AG - Photography - M9 & M9-P and click on the Technical Data link. Non linear reduction of color depth means lossy.
    Too bad, I guess there is no free lunch today. Thanks for the info Mirek. So back to uncompressed it is.

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    Re: Compressed VS Uncompressed DNGs - A quick test

    Quote Originally Posted by MirekE View Post
    Is the AdobeRGB really big enough for you? The following diagrams show pixels from a picture of an ordinary tree with green leaves plotted into the CIE chromaticity "horseshoe". The three triangles are gamuts of sRGB, AdobeRGB and ProPhoto RGB. One diagram is exported as ProPhoto and one as AdobeRGB. As you can see, lots of the greens had to be remapped from its original color to fit inside AdobeRGB. So using AdobeRGB meant in this particular case throwing away data - something that you apparently like to avoid...



    ^^This looks like a translation from ProphotoRGB to AdobeRGB with a relatively colorimetric rendering intend. Using a preceptive rendering intend would have slightly moved all the colors. Though I'm no expert on this topic and I admit I might very well be wrong...
    You have to admit that this is all a bit theoretical. According to the images it looks like it has a larger impact on a print than it usually does. "Usually" because I personally am a fan of muted colors and I rarely print highly saturated images. The images from the test are just my attempt to cause banding but I never increase saturation or vibrance.

    But you are right, I thrive for ultimate quality so I'll continue using uncompressed raws and my color management with ProphotoRGB.


    Regards

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    Re: Compressed VS Uncompressed DNGs - A quick test

    Quote Originally Posted by MirekE View Post
    Your shots look like there is no difference. But document on a Leica site says "choice of uncompressed or slightly compressed (by non-linear reduction of color depth)" - go to Leica Camera AG - Photography - M9 & M9-P and click on the Technical Data link. Non linear reduction of color depth means lossy.

    Yep, here's an excerpt from the M page on Facebook, posted by Zalman Stern (a friend and colleague):

    Zalman Stern (I am the former tech lead on Camera Raw at Adobe.)

    The M Type 240 implements DNG Lossless Compression, which is in fact lossless. (The method used is Lossless JPEG as in many vendor proprietary raw formats.) I do not know why Leica left in the option for Uncompressed DNG. Perhaps they use it in debugging or there is a customer built workflow tool that required uncompressed DNG. I would be in favor of the option being removed, especially if DNG Proxy format support is added in the future. (DNG Proxy allows for lossy compressed and subsampled raw files, similar to e.g. mRAW and sRAW on Canon cameras, though significantly better in quality for a given file size.)

    Compressed DNG on the M8, M9, and M-E series of cameras is lossy, though it is hard to make a case that it is visually detectable. The method used transforms the linear raw data via a perceptual curve and quantizes to 8-bit. Hence the constant output size and minimal visual degradation.

    One can take Uncompressed DNGs from any M and reconvert them with the Adobe DNG Converter to get approximately a factor of 2 smaller file with no loss of visual information or metadata. Even if one wants to preserve exactly the bits from the camera in one's permanent archive, this is extremely useful for keeping more files on a laptop or for extra backup copies.

    Slightly related to the discussion, if one has lens detection turned on for cameras before the Type 240, vignette correction is done destructively to the raw data. I do not know of a way to have lens metadata written to the file without vignette correction being applied. Ideally this would be done by writing DNG lens correction metadata (opcodes) to the DNG file instead of via modifying the raw samples themselves. Perhaps it is done this way in the M Type 240. I have not had an opportunity to investigate.
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    Re: Compressed VS Uncompressed DNGs - A quick test

    By the way I should add that what Zalman suggests is what I used to do with the M9. Shoot with it uncompressed on camera and then convert to DNG on a computer getting the lossless compression.
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    Re: Compressed VS Uncompressed DNGs - A quick test

    Quote Originally Posted by MirekE View Post
    Is the AdobeRGB really big enough for you? The following diagrams show pixels from a picture of an ordinary tree with green leaves plotted into the CIE chromaticity "horseshoe". The three triangles are gamuts of sRGB, AdobeRGB and ProPhoto RGB. One diagram is exported as ProPhoto and one as AdobeRGB. As you can see, lots of the greens had to be remapped from its original color to fit inside AdobeRGB. So using AdobeRGB meant in this particular case throwing away data - something that you apparently like to avoid...
    It depends on the rendering.

    You also still missed my point of the coordinate space. You get no more possible colors in a color space. You see the image does not fill the colors spaces. The larger the color space, the greater the distance between the colors. A larger colors space will have to do more binning (and as you illustrate, ProPhotoRGB will always have empty coordinates as simply it has "colors" that cannot be perceived). And ultimately you will need to fit your image to a print space. So even with the image you are using, I could still end up with less data using ProPhotoRGB.

    Now, if you read my post, what I said was not to automatically default to ProPhotoRGB. I never said not to use it.

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    Re: Compressed VS Uncompressed DNGs - A quick test

    Quote Originally Posted by MaxKi▀ler View Post
    ^^This looks like a translation from ProphotoRGB to AdobeRGB with a relatively colorimetric rendering intend. Using a preceptive rendering intend would have slightly moved all the colors. Though I'm no expert on this topic and I admit I might very well be wrong...
    You have to admit that this is all a bit theoretical. According to the images it looks like it has a larger impact on a print than it usually does. "Usually" because I personally am a fan of muted colors and I rarely print highly saturated images. The images from the test are just my attempt to cause banding but I never increase saturation or vibrance.

    But you are right, I thrive for ultimate quality so I'll continue using uncompressed raws and my color management with ProphotoRGB.


    Regards
    And how you determine "quality"? By looking at the results? In this post you claim you cannot see the difference between compressed and uncompressed files. And this is an important point. A photograph is made for a viewer. The numbers and specs do not indicate if an image is pleasing--"pleasing" is a technical term meaning that it looks good to a viewer. And you should be judging a photograph by its appearance--seeing is believing in photography (if it looks bad, it is). Since a photograph is a visual stimuli, how does the technical specifications converge and diverge from that experience? Photography, while it tries to imitate human vision, it does it in an artificial way. Photographers like to argue over the numbers, but the results are what are important. Which is probably why we argue over them so much--MFD is king, the D800 is the MFD killer, m4/3 is better than FF, etc. So, were does "quality" come from?

    Now, if you do like more of a muted palette, ProPhotoRGB will use fewer coordinates. A smaller gamut will use more. The greatest thing about RAW is that you can open a file into any gamut you want and as many as you want. Perhaps try opening a file in both ProPhotoRGB and AdobeRGB and process both and see how they are. If you use fairly complex curves to process, you may find one color space better than the other.

    I guess for me, the color space is just another choice on the way to the final image. Just like exposure, lighting, and a whole host of other factors.

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    Re: Compressed VS Uncompressed DNGs - A quick test

    Shooting raw, colorspace is just a metadata tag.
    That is why I shoot raw and nothing else (well, occasionally I will shoot both simultaneously).
    Processing raw into a working space that is as large as possible then matching colorspace post-edit to the output device.
    It is usually best to minimize the number of colorspace conversions. Conversion from large to small and back again is a sure way of losing information.
    -bob
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    Re: Compressed VS Uncompressed DNGs - A quick test

    Quote Originally Posted by MaxKi▀ler View Post
    ^^This looks like a translation from ProphotoRGB to AdobeRGB with a relatively colorimetric rendering intend. Using a preceptive rendering intend would have slightly moved all the colors. Though I'm no expert on this topic and I admit I might very well be wrong...
    You have to admit that this is all a bit theoretical. According to the images it looks like it has a larger impact on a print than it usually does. "Usually" because I personally am a fan of muted colors and I rarely print highly saturated images. The images from the test are just my attempt to cause banding but I never increase saturation or vibrance.

    But you are right, I thrive for ultimate quality so I'll continue using uncompressed raws and my color management with ProphotoRGB.


    Regards
    These diagrams are reaction to a post suggesting that using ProPhoto RGB can lead to data loss. I wanted to demonstrate that actually using AdobeRGB leads to data loss. There are clearly colors outside of AdobeRGB in a trivial shot of a tree that must be remapped.

    With regards to your suggestion to use perceptual intent, LR does not allow that and I was told in a color management forum recently that there is no such thing as perceptual intent between these color spaces, as they do not have LUTs. In any case, what you see here is not a conversion from ProPhoto to AdobeRGB, these are both direct conversions from raw.

    Whether this is only theoretical or not - this is the picture in ProPhoto, if you want to soft proof it on your own:



    I use Lightroom, so yes, it is theoretical for me, because I don't store images in their cooked form anymore. I just think it is good to know about the limitations. AdobeRGB can clip greens, on the other hand, some photographers claim that ProPhoto caused posterization in skin tones in their studio shots. Pick your own poison...

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    Re: Compressed VS Uncompressed DNGs - A quick test

    Quote Originally Posted by MaxKi▀ler View Post
    Too bad, I guess there is no free lunch today. Thanks for the info Mirek. So back to uncompressed it is.
    Some people said they had visible loss of detail in busy areas of their images, so you may want to do some test on subjects that have lots of color detail. I used uncompressed with M9, because it is safer and does not cost anything.

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    Re: Compressed VS Uncompressed DNGs - A quick test

    Quote Originally Posted by Shashin View Post
    You also still missed my point of the coordinate space. You get no more possible colors in a color space. You see the image does not fill the colors spaces. .
    No, I did not. I did not comment on it because I don't have the knowledge to comment. I have never seen posterization with 16bit ProPhoto. Some people claim it exists though and I am not going to say it does not exist.

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    Re: Compressed VS Uncompressed DNGs - A quick test

    So what I've learned in this thread, and if I'm wrong please tell me, but I've been shooting in uncompressed DNG on my M9. So I just experimented with Lightroom's "Convert to DNG" on import with a couple of my M9 files. In the past I've just used the "Copy" to new location option. Well I after import using the Convert to DNG option I'm saving quite a bit of space. 36mb files down to 18 - 21mb files.

    So this will be my new way to import as long as I understand that by converting to DNG a second time I've created a lossless DNG that has not lost any of the original "RAW" data the camera created.
    Duane Pandorf
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    Re: Compressed VS Uncompressed DNGs - A quick test

    Quote Originally Posted by Shashin View Post
    And how you determine "quality"? By looking at the results? In this post you claim you cannot see the difference between compressed and uncompressed files. And this is an important point. ...

    Now, if you do like more of a muted palette, ProPhotoRGB will use fewer coordinates. A smaller gamut will use more. The greatest thing about RAW is that you can open a file into any gamut you want and as many as you want. Perhaps try opening a file in both ProPhotoRGB and AdobeRGB and process both and see how they are. If you use fairly complex curves to process, you may find one color space better than the other.

    ...
    An idea comes first, this should go without saying (content beats technique - always). My definition of quality was in regard to the technical aspects of a photograph. Having a vast color palette and getting the maximum achievable resolution is of importance to me.

    I know I said that I do not see any difference whether I shoot compressed or uncompressed DNGs. And admittedly, I never process a file as intensely as in the test above so that I should never see a difference. But knowing that I'm basically throwing away color information in a compressed raw is something I cannot deal with. It's the fact that there is the eventuality that a certain image could be "better" that is very unapppealing to me.


    "ProPhotoRGB will use fewer coordinates. A smaller gamut will use more." This should not affect anything. ProphotoRGB is a larger color space but that doesn't change the location of particular tones in the entire color space.

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    Re: Compressed VS Uncompressed DNGs - A quick test

    Quote Originally Posted by MirekE View Post
    I just think it is good to know about the limitations. AdobeRGB can clip greens, on the other hand, some photographers claim that ProPhoto caused posterization in skin tones in their studio shots. Pick your own poison...
    I have never seen a hint of that assuming a good workflow. Converting a jpeg shot in sRGB to pro photo, working on it for awhile, then moving back to sRBG, yes that would tend to cause problems.
    -bob

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    Re: Compressed VS Uncompressed DNGs - A quick test

    Quote Originally Posted by MirekE View Post
    These diagrams are reaction to a post suggesting that using ProPhoto RGB can lead to data loss. I wanted to demonstrate that actually using AdobeRGB leads to data loss. There are clearly colors outside of AdobeRGB in a trivial shot of a tree that must be remapped.

    With regards to your suggestion to use perceptual intent, LR does not allow that and I was told in a color management forum recently that there is no such thing as perceptual intent between these color spaces, as they do not have LUTs. In any case, what you see here is not a conversion from ProPhoto to AdobeRGB, these are both direct conversions from raw.

    Whether this is only theoretical or not - this is the picture in ProPhoto, if you want to soft proof it on your own:



    I use Lightroom, so yes, it is theoretical for me, because I don't store images in their cooked form anymore. I just think it is good to know about the limitations. AdobeRGB can clip greens, on the other hand, some photographers claim that ProPhoto caused posterization in skin tones in their studio shots. Pick your own poison...

    You're right, there is a visible difference in the greens. Especially in the green of the pine trees. I said it was theoretical because in a print it will hardly make a difference as most printer's color spaces are much smaller anyway. So both ProphotoRGB and AdobeRGB would get scaled down to match that particular printer's color space.

    If these are both conversions from raw data it shouldn't make a difference which color space is assigned to the image. As long as there have not been made any permanent conversions to a certain color space it will only make a difference in the way it's being displayed. That's why LR doesn't have internal rendering specifications/preferences.

    ----


    My rule of thumb is: Use the largest possible color space and use the right rendering intent when scaling down to the output color space. That's why it's important to me to know whether shooting compressed raw yields the same quality as uncompressed raw. If the (color) information isn't there in the first placce, using a large color space such as ProphotoRGB won't make much sense.

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    Re: Compressed VS Uncompressed DNGs - A quick test

    ... in a print it will hardly make a difference as most printer's color spaces are much smaller anyway. So both ProphotoRGB and AdobeRGB would get scaled down to match that particular printer's color space.
    Probably depends on the printer. I have some profiles for low gamut Epson papers for 3880 here and when I compare them with AdobeRGB, none of them fit inside. There are usually blues and yellows that stick out, but with same papers also greens and reds. I posted an example earlier in this thread.

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    Re: Compressed VS Uncompressed DNGs - A quick test

    Quote Originally Posted by MaxKi▀ler View Post

    My rule of thumb is: Use the largest possible color space and use the right rendering intent when scaling down to the output color space. That's why it's important to me to know whether shooting compressed raw yields the same quality as uncompressed raw. If the (color) information isn't there in the first placce, using a large color space such as ProphotoRGB won't make much sense.
    I think the differences are very small, but they all contribute. If I use lossy compression and clip colors and use cheap paper for printing and skimp on display and do not calibrate and use cheap filters...

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    Re: Compressed VS Uncompressed DNGs - A quick test

    So, ProPhoto RGB is the way to go for greater accuracy. For mere mortals which monitors are you guys using that support ProPhoto RGB? It seems to me that if the monitor doesn't support it (you can see the difference) you would just end up printing random colours you knew nothing about at the post processing stage. Even if the full gamut of Adobe RGB isn't shown by many monitor's/screens (even though they operate in it) it surely can't help to go even bigger and further into the unknown with ProPhoto? I'm sure it won't be a cheap solution.

    Steve

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    Re: Compressed VS Uncompressed DNGs - A quick test

    Quote Originally Posted by 250swb View Post
    So, ProPhoto RGB is the way to go for greater accuracy. For mere mortals which monitors are you guys using that support ProPhoto RGB? It seems to me that if the monitor doesn't support it (you can see the difference) you would just end up printing random colours you knew nothing about at the post processing stage. Even if the full gamut of Adobe RGB isn't shown by many monitor's/screens (even though they operate in it) it surely can't help to go even bigger and further into the unknown with ProPhoto? I'm sure it won't be a cheap solution.

    Steve
    Not sure about the greater accuracy. In my view, it is a way to avoid premature clipping of colors.

    CRT monitors had approximately gamut of sRGB and it did not prevent prepress studios from working in AdobeRGB even though their printing mistakes would have been very expensive, compared to reprinting an inkjet print.

    The colors are not printing "random", the greens from my diagram won't turn purple or orange. They will just display slightly differently. Having inaccurate preview is quite normal for "mere mortals" anyways, for many other reasons than using ProPhotoRGB as a working space.

    There are, to my knowledge, three ways to learn something about the out of gamut colors.

    • Soft proof with gamut clipping preview will show the areas that are impacted
    • Photoshop has an option to desaturate all colors, allowing the whole scale to show up, albeit in lower saturation
    • Test print

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    Re: Compressed VS Uncompressed DNGs - A quick test

    Quote Originally Posted by 250swb View Post
    So, ProPhoto RGB is the way to go for greater accuracy. For mere mortals which monitors are you guys using that support ProPhoto RGB? It seems to me that if the monitor doesn't support it (you can see the difference) you would just end up printing random colours you knew nothing about at the post processing stage. Even if the full gamut of Adobe RGB isn't shown by many monitor's/screens (even though they operate in it) it surely can't help to go even bigger and further into the unknown with ProPhoto? I'm sure it won't be a cheap solution.

    Steve
    I use an Eizo CG276.
    Shooting in raw, converting to 16 bit tiffs with a ProPhoto colorspace before working in PS.
    Of course my monitor is calibrated as are my printer/paper combinations and I edit with proofing set to the selected destination profile.
    A very good book on the subject is "Color management, Understanding and using icc profiles" Wiley2010 ISBN: 978-0-470-05825-1
    -bob
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    Re: Compressed VS Uncompressed DNGs - A quick test

    Quote Originally Posted by MaxKi▀ler View Post
    "ProPhotoRGB will use fewer coordinates. A smaller gamut will use more." This should not affect anything. ProphotoRGB is a larger color space but that doesn't change the location of particular tones in the entire color space.
    Why? Don't you like higher bit depths? All the tones are in the same place in the visual gamut with an 8-bit or 16-bit image, you just don't have as many with 8-bit. This is what effectively happens with different gamut sizes with a given image gamut--ProPhotoRGB can results in fewer discrete colors. That could be important if you process your images. That is just how color is encoded in gamuts.

    Max, if you have a system that works for you and you are pleased with it, that is great. It is all you need. Which is just showing your point in this thread about the insignificance of things like compression and the chase for the "best" image quality is rather pointless, at least if it is done by specs. I was just pointing out that folks use specs because they think they are getting more when they can actually be getting less, ProPhotoRGB is just an example of that.

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    Re: Compressed VS Uncompressed DNGs - A quick test

    Quote Originally Posted by Shashin View Post
    I was just pointing out that folks use specs because they think they are getting more when they can actually be getting less, ProPhotoRGB is just an example of that.
    Do you have any tips on types of images or situations where this could be a problem? I hear about this often, but I was never able to reproduce any banding/posterization issues coming from the fact that ProPhoto has large gamut. If there are, I would like to be able to demo it the same way I demoed the color clipping.

    I try to keep open minded about this, but it is hard. Example: ProPhoto gamut volume is only about twice as big as AdobeRGB. If AdobeRGB is just fine for 8 bit processing, why 16-bit (256x larger) precision is not enough for ProPhoto?

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    Re: Compressed VS Uncompressed DNGs - A quick test

    Quote Originally Posted by Bob View Post
    I use an Eizo CG276.
    Shooting in raw, converting to 16 bit tiffs with a ProPhoto colorspace before working in PS.
    Of course my monitor is calibrated as are my printer/paper combinations and I edit with proofing set to the selected destination profile.
    A very good book on the subject is "Color management, Understanding and using icc profiles" Wiley2010 ISBN: 978-0-470-05825-1
    -bob
    Yes we all know about calibrated monitors etc. but if you can't see what a colour space does for you, why use it? It is adding additional information at the printing stage that you can't see on your monitor, so it's a crap shoot, you glory in it when it goes well, you go back to stage one (something closer to what you see on the monitor) when it does things you don't expect. ProPhoto is a great idea but if it isn't seen on a monitor how can it convey what you want in post processing?

    Steve

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    Re: Compressed VS Uncompressed DNGs - A quick test

    Quote Originally Posted by MirekE View Post
    Do you have any tips on types of images or situations where this could be a problem? I hear about this often, but I was never able to reproduce any banding/posterization issues coming from the fact that ProPhoto has large gamut. If there are, I would like to be able to demo it the same way I demoed the color clipping.

    I try to keep open minded about this, but it is hard. Example: ProPhoto gamut volume is only about twice as big as AdobeRGB. If AdobeRGB is just fine for 8 bit processing, why 16-bit (256x larger) precision is not enough for ProPhoto?
    Well, I know a few folks here at GetDPI that have had banding with 8-bit ProPhotoRGB. Since I don't use PhotoPhotoRGB that much and they are very experienced photographers, I had no doubt they had experienced this. I know of one fine art photographer who I help with printing her exhibition work have some difficulty with bring some detail out in some dark saturated areas of an image and it seemed that the ProPhotoRGB gamut was contributing to it.

    But I am not talking about posterization. I am talking about optimizing the color gamut to the image. You can also make very nice images from underexposed files, but I prefer to optimize my exposures as well. If you have the perfect 8-bit image, a 16-bit image will look no different. My arguments, and I think that you keep missing this, is not that ProPhotoRGB will not give good results, it will, but that if you are really trying to optimize your data, then the choice of color space will be part of that.

    I will say this again: if you have a workflow that gives you good results, great, go with that. I have a workflow that works for me and I am just sharing a thought with that.
    Will

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    Re: Compressed VS Uncompressed DNGs - A quick test

    But I am not talking about posterization. I am talking about optimizing the color gamut to the image. You can also make very nice images from underexposed files, but I prefer to optimize my exposures as well. If you have the perfect 8-bit image, a 16-bit image will look no different. My arguments, and I think that you keep missing this, is not that ProPhotoRGB will not give good results, it will, but that if you are really trying to optimize your data, then the choice of color space will be part of that.
    Yes, I think I am missing this. Would you mind giving an example?

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