Thread: Komodo 12.2 stops of dynamic range in CineD test.

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  1. #41  
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    Quote Originally Posted by Noah Yuan-Vogel View Post
    Also there is no mention of the fact that you can clearly see in their komodo waveform that the top two stops of DR appear to rely entirely on the built-in highlight recovery which may only work for monochromatic detail at certain whitebalances among other issues with it. And then I wonder if one were to use highlight recovery in post on the arriraw or C300iii raw if they would also benefit from an additional 1-2 stops of DR from highlight recovery. Definitely seems like a problematic issue to face. From some of the other tests I've seen, it does appear those highlight recovery stops really cannot be relied upon for certain kinds of tones and detail, but they may particularly improve the apparent results of a monochromatic xyla chart...
    This is the concern I'm talking about, and why I'm not totally convinced with 'the xyla was done wrong' claim either... Even if the charts are done wrong, the weak highlight performance (poorly balanced over/under DR) still remains and is something I've noticed with MX, Dragon and Helium (to varying degrees).

    Case in point, CineD only being able to recover +1 skintone highlight accurately, when the p6k recovered +4. That's a huge difference, which requires counterintuitive tricks to minimize (but still not remedy entirely)... And if those same measures are applied to footage from other cameras (unnecessarily, if they have comparatively balanced over/under), would they have similarly (usable) DR gains?

    This isn't a weakness that shows up in the monochrome charts. It shows up in post, when the high side isn't just hot, it's burned/clipped (even though it only measured +3). Is it the end of the world? No, if you know about it you can compensate/alleviate. Does it make your job more difficult than it needs to be? Yeah, I think so.
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  2. #42  
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    Not sure how to judge this particular dynamic range test. But on the bright (haha) side, one great thing about the Komodo vs. other cameras is that the goal posts and stop lights help you get the most out of the dynamic range you DO have. I've been shooting test footage outside in high contrast situations, and it's these tools that really make the difference.
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  3. #43  
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    Same link Bastian posted, but linking their test video here.



    https://www.repaire.net/forums/artic...NhpFtro5MvLk4k

    Worth a translate and read, but mostly look at the footage. Decent side by sides.
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  4. #44  
    Gentlemen,

    this is my first post on reduser and I am the guy who is doing the CineD Lab tests. I am here to answer all your questions, and looking forward to a good technical discussion.

    Phil has shared already our method (how we test) - thank you - and in the article I have clearly laid out the dilemma one has when trying to reduce DR to a single number.


    https://www.cined.com/the-cinema5d-c...c-range-tests/

    a) Judging DR only from waveforms is a good method, but subjective, as some may see more stops than others and it doesn't tell you if all those stops are usable are not. USABLE is the term here!

    b) The Xyla 21 chart has to be shot at 3200K - agreed. Nevertheless we purposely expand the RGB information to 5600K to see if all color channels are still there. In the french test shared by Bastien (previous page) you can clearly see the lacking color information on the top 2 stops of the KOMODO. Why, because Komodo uses an in - built highlight recovery mechanism (as the first RED camera). In the facebook thread where our lab results are discussed (RED KOMODO group), the man behind the IPP2 image pipeline himself, Graeme Nattress has confirmed this behaviour for the KOMODO, see attached screenshot.

    c) IMATEST is the only objective way to mathematically calculate signal to noise numbers for each patch and hence dynamic range. Is it perfect - no. Because as Phil mentioned, flares can have an impact on the result, etc.. But it is a way to quantify and compare cameras to each other. We are conservative and use the Signal to noise ratio = 2 as our definition of usable (but give you both SNR = 1 and 2 values for full transparency).

    d) Of course, in-camera or post noise reduction has an influence on the calculated signal to noise numbers. With noise reduction, the signal stays the same but noise is reduced, leading to a higher signal to noise value thus higher dynamic range. THe same happens by downsampling from 6K to 4K or to FullHD. IMATEST themselves warn against using noise reduction, and suggest to use RAW files as pure as possible, otherwise results will be distorted - as has been pointed out earlier in this thread as well. Thats why we give you pure values straight from the file with no post processing at native resolution.

    e) on shooting the chart wrong: here is the download link for the R3D HQ file shooting our Xyla21 chart, judge yourself: https://we.tl/t-c1YhxlHqWj

    f) and finally, we are also doing the latitude test, purposely over- and underexposing and bringing it back to see how usable the dynamic range is. To have a reference we choose a max. luma value of 60% for the subject's face. Which is hot for some cameras like the KOMODO but in the middle for others - the ALEXA for example has five usable stops above 60% Luma, the BMPCC6K has close to 4 stops, the C300MKII has 3 usable stops above 60% - that is just a matter how cameras distribute the stops across the range, which also depends on the ISO you choose e.g. for the KOMODO. And this test confirms that two stops above 60% at ISO800 the face cannot be recovered - that is exactly the stop from the waveform which has already clipped color channels but still looks good in the waveform (due to HL recovery - or soft roll off, however you want to call it).

    Happy to answer any other questions you might have!

    best regards, Gunther
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    Last edited by Gunther Machu; 01-22-2021 at 12:58 AM.
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  5. #45  
    Senior Member Bastien Tribalat's Avatar
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    Quote Originally Posted by Gunther Machu View Post
    Gentlemen,

    this is my first post on reduser and I am the guy who is doing the CineD Lab tests. I am here to answer all your questions, and looking forward to a good technical discussion.

    Phil has shared already our method (how we test) - thank you - and in the article I have clearly laid out the dilemma one has when trying to reduce DR to a single number.


    https://www.cined.com/the-cinema5d-c...c-range-tests/

    a) Judging DR only from waveforms is a good method, but subjective, as some may see more stops than others and it doesn't tell you if all those stops are usable are not. USABLE is the term here!

    b) The Xyla 21 chart has to be shot at 3200K - agreed. Nevertheless we purposely expand the RGB information to 5600K to see if all color channels are still there. In the french test shared by Bastien (previous page) you can clearly see the lacking color information on the top 2 stops of the KOMODO. Why, because Komodo uses an in - built highlight recovery mechanism (as the first RED camera). In the facebook thread where our lab results are discussed (RED KOMODO group), the man behind the IPP2 image pipeline himself, Graeme Nattress has confirmed this behaviour for the KOMODO, see attached screenshot.

    c) IMATEST is the only objective way to mathematically calculate signal to noise numbers for each patch and hence dynamic range. Is it perfect - no. Because as Phil mentioned, flares can have an impact on the result, etc.. But it is a way to quantify and compare cameras to each other. We are conservative and use the Signal to noise ratio = 2 as our definition of usable (but give you both SNR = 1 and 2 values for full transparency).

    d) Of course, in-camera or post noise reduction has an influence on the calculated signal to noise numbers. With noise reduction, the signal stays the same but noise is reduced, leading to a higher signal to noise value thus higher dynamic range. THe same happens by downsampling from 6K to 4K or to FullHD. IMATEST themselves warn against using noise reduction, and suggest to use RAW files as pure as possible, otherwise results will be distorted - as has been pointed out earlier in this thread as well. Thats why we give you pure values straight from the file with no post processing at native resolution.

    e) on shooting the chart wrong: here is the download link for the R3D HQ file shooting our Xyla21 chart, judge yourself: https://we.tl/t-c1YhxlHqWj

    f) and finally, we are also doing the latitude test, purposely over- and underexposing and bringing it back to see how usable the dynamic range is. To have a reference we choose a max. luma value of 60% for the subject's face. Which is hot for some cameras like the KOMODO but in the middle for others - the ALEXA for example has five usable stops above 60% Luma, the BMPCC6K has close to 4 stops, the C300MKII has 3 usable stops above 60% - that is just a matter how cameras distribute the stops across the range, which also depends on the ISO you choose e.g. for the KOMODO. And this test confirms that two stops above 60% at ISO800 the face cannot be recovered - that is exactly the stop from the waveform which has already clipped color channels but still looks good in the waveform (due to HL recovery - or soft roll off, however you want to call it).

    Happy to answer any other questions you might have!

    best regards, Gunther
    Thank you for your post.
    I didn't say this here but said it on Facebook (in Emmanuel Pampuri's Facebook Group "Geek Lumineux") : I am NOT saying that your testing was bad or not trustworthy and the french one is or vice versa. They are just two tests to get perspective on a specific matter.
    And thank you so much for sharing the file I will test it myself just to get an opinion ON THE CAMERA, not on your method. ;-)

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  6. #46  
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    DR stops aside, the most interesting thing about all of this is the top stop of monochrome highlight. While I don’t think it’s much of a problem if you don’t screw up totally while shooting and that the Pocket 6K isn’t close to the color science of Komodo so its benefits in highlight stop quality aren’t enough for the rest of it, I don’t get why Komodo doesn’t have color in that part of the DR spectrum?

    What is the reason for it? Is this “the magic” that enabled a global shutter to reach enough stops that previous global shutters did not? Is it built in or through the color science? Is it “fixable”?

    I can’t really figure out the logic behind it?
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  7. #47  
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    Quote Originally Posted by Christoffer Glans View Post
    DR stops aside, the most interesting thing about all of this is the top stop of monochrome highlight. While I don’t think it’s much of a problem if you don’t screw up totally while shooting and that the Pocket 6K isn’t close to the color science of Komodo so its benefits in highlight stop quality aren’t enough for the rest of it, I don’t get why Komodo doesn’t have color in that part of the DR spectrum?

    What is the reason for it? Is this “the magic” that enabled a global shutter to reach enough stops that previous global shutters did not? Is it built in or through the color science? Is it “fixable”?

    I can’t really figure out the logic behind it?
    I'm in no way a sensor engineer but to me it doesn't seem to be related to the global shutter since on the french test the C300MKIII seems (at least to me) to have kinda the same characteristics.
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  8. #48  
    On the subject of noise reduction, I think it's perfectly reasonable to report numbers as long as the NR type and parameters are reported. 1-frame TNR in Resolve does a great job reducing shadow noise in RAW files. Not so much for mpeg-encoded files with macro blocking. Similarly, RED's Chroma Noise Reduction also works very well at calming things down and increasing SNR.

    Almost all astrophotography photos use extensive NR, and it would be almost meaningless to try to evaluate the merits of a given imaging platform without consideration of how that platform supports (or prevents) the application of NR techniques essential to the craft.

    Of course we don't expect testing orgs to run through every NR technique with every possible parameter setting that forces us to sift through 50,000 results to find the one that's most meaningful to us. But I don't think it's wrong to acknowledge when a very straightforward approach leads to a significant change in final results.
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  9. #49  
    Regarding waveform analysis, my benchmark is this: after white balancing the steps, if there is a distinct empty space below the step I count it as resolved DR. If there's a series of decreasing steps that all merge into the noise floor without visible gaps below, I count that as not resolved. If the bottom noise hairs overlap < 5% the top noise hairs of the next lower step, I consider that USEABLE because a key can adequately distinguish the two.
    Last edited by Michael Tiemann; 01-22-2021 at 04:59 AM. Reason: Chang completely to adequately
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  10. #50  
    Senior Member Bastien Tribalat's Avatar
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    Here are my results after playing with Gunther's file.
    IT IS NOT A SCIENTIFIC APPROACH.

    Workflow is 6K timeline, Full Res PREMIUM decoding and that's it, everything else is specified.

    Note : "Manual NR" = 3 frames/faster/medium and everything around 30-ish | SNR Enhanced, Small and again everything around 30-ish.

    I repeat : it's just me playing with the file, nothing more.
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