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sunyata

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Posts posted by sunyata

  1. Ah, bang goes the dynamite. I was actually just laughing at how cantankerous these forums are, not you specifically. But if you want to talk about screw ups, these are your words:

    People are too focused on 10-bit versus 8-bit, when the-real-difference between 4:2:2 and 4:2:0 is higher than 10-bit 4:2:2 vs 8-bit 4:2:2.

    This is not correct but I understand how one could think that from that Shogun test, to be fair. The radial I used was not initially monochrome btw, it was de-saturated to try to closely match the source test you referenced. "nice try to decompress with that Marcie one haha".. I'm not even sure what that means. I said "maybe" 3 times in a sentence to underline how many possible variables could be introduced in the Shogun test, i.e. "Maybe this, maybe that, who knows." 

    "Or have hard chance to publicly accept they are as much ordinary as the others."  " We all suffer of such need of love. Everyone in the same boat." Okay, now I'm in a 12 step program? 

  2. lol, the marcie is just FPO. This is a gamma test of S-Log2 vs S-Log3 with an 8bit intermediate pipeline. I think the banding in the toe for the S-Log3 looks better than S-Log2 (top right ramps) and clearly more contrast below like 6% is retained (bottom chart). Highlights aren't really as different as I was expecting. S-Log3 should be a little brighter but I can barely notice it. 

  3. Emanuel, it's a really simple test to replicate, please feel free to try. I was working on a different test more related to this topic of the A7sII and S-Log3 when I got distracted by that Vimeo link. Here's the S-Log-3 test: 

    slog2v3_8bit_marcie.png

    I was rendering a 3D project, I swear I don't just do tests all day. 

  4. sunyata, read the post of Karim... :-)

    Check out the results of the updated image if you want to see a different radial used to start with... both radials have more banding as you would expect, but the 4:2:2 is marginally better; I think quite a few people wouldn't know the difference. 

  5. It's true that some colors degrade more than others, but because the source radial was generated in RGB space and converted to Y'CbCr, you will still see chroma subsampling artifacts (it still get's subsampled in Cb and Cr to compose the final image). I was comparing with the other test, which looks grayscale, but in the past I've preferred to test this with random animated colors just to see where most breakup happens. I've updated the image to use a lot of red, typically the worst color.

    radial_420test.png

     

  6. Who said 4:2:2 is more important than 10-bit? The difference between 8-bit 4:2:2 and 8-bit 4:2:0, it is more significant for your grading. Much different statement. Of course, for certain type of grading. No mention of raw or alike where even 10-bit is short by default. People too much focused on the 10-bit holy grail tend to forget ; ) But, banding was the topic (hence my "the-real-difference" of my post; numbers help but like machines need i-n-t-e-r-p-r-e-t-a-t-i-o-n :-D) :

    http://www.eoshd.com/comments/topic/9390-sony-a7s-ii-is-out/?do=findComment&comment=106562

    Speaking of math, let's see with a very simple case: 1) 100,000; 2) 1,000,000; 3) 10,000,000. Where's the bigger difference? Now, take these figures as bucks and your single expense as any number between 100,000 and 1,000,000. Which step will make the whole difference?

    Here goes your single example on pictures, posted and reposted more than once:

    http://www.eoshd.com/comments/topic/9355-canon-announces-development-of-8k-cinema-eos-camera-and-120mp-dslr/?do=findComment&comment=105935

    Oh my, I never saw that one. There is a little flaw in his test that probably explains the huge difference between the demonstrated quality of 8bit 4:2:0 vs 8bit 4:2:2: he's recording externally to the Shogun with the 8bit 4:2:2 and internally to the GH4 for the 4:2:0. I'm gonna bet a dollar that's why they look so different. Maybe it's a data rate thing, maybe its smoothing happening with the Shogun, Maybe it's the GH4's implementation of 8bit 4:2:2, I don't know. Below is just a radial saved as 8bit dpx, then two conversions to respective chroma subsampling schemes. One is yuv420p 8bit and the other is yuv422p 8bit,  Same very high h264 constant bitrate settings for both. Re-imported, gamma curve applied and saved out as a sRGB png.

    radial_420test.png

     

     

  7. Well since most people can only perceive about 1 million colors and only one person has been discovered that had the wetware to perceive more, it might not matter.

     

    If you have 8-bit systems, you can install all the log that you want, but you will always have 8-bit, 10-bit point was needed,  you can always correct it shortly with 8-bit color.

    8 bit = 16,777,216 possible colors

    10 bit = over a billion possible colors

    Just to address both of these comments, even though they are disagreeing, the total number of colors per pixel is kind of a useless metric. Nobody will ever ask you "Hey, can you save that file out 1,073,741,824 colors please?", they'll just ask for 10bit, 12bit etc. This is because the total number of possible colors per pixel is not only impossible to remember, is not really what determines noticeable quality issues; that's contrast. You get 256 or less for 8bit, 1024 for 10bit etc. 

  8. If you're mainly interested in color that you can actually correct for sRGB display space, then the inclusion of S-Gamut3.Cine is likely the big news. 

    "S-Gamut3.Cine is similar to negative film scan which was used for TV production, film out digital cinema. Color reproduction is designed slightly wider than DCI-P3 to provide ample room for grading. Thus manual grading for P3 becomes easier. S-Gamut3.Cine is more convenient to grade than S-Gamut3 and S-Gamut as camera digital negative. If you would like to apply print film emulation, please increase saturation to about 1.4."

    sgamut3cine.jpg

    Can never get enough plots. 

     

  9. Slog3 might put a little more strain on the highlight noise level in 8bit 4:2:2, but I think that will largely be forgotten in exchange for the color benefits of encoding in S-Gamut3.Cine, which people should find much easier to color correct; It's closer to a negative film scan.

  10. Assuming you haven't seen this.. it looks like cameramanben has done something really useful here: he's compiled a ton of research and written a JavaScript LUT calculator tool released under a GNU freesoftware license (I think this is about as free as it gets). This could be used for 1D shaper LUT's, or 3D LUT's with gamma/gamut baked together - if that's more your thing - and even custom code value ranges. I think you can upload a sample image too. I see an A7s profile as well as Rec2020 gamut, DCI-P3 gamut... it's on github.

    Online tool: http://cameramanben.github.io/LUTCalc/LUTCalc/index.html

    Link to browser based apps: https://cameramanben.github.io/LUTCalc/

    Objective-C wrapper for MacOS: https://github.com/cameramanben/LUTCalc-For-Mac 

    He needs a donation button somewhere. 

     

  11. Strange, they had 37.6mm diagonal for the D800, but even if you compensate for a vertical 16:9 crop when shooting 1.78, you get 41.1. from the width of 35.9, If you just calculate the full sensor you get 43.2mm diagonal. I'm going to put it in at 41.1, not sure how they got the 37.6mm diagonal. Do you get the full width of the sensor when shooting video?

  12.  

    Mh, interesting. I find myself needing to color correct my shots as well, so when i am not finding some white as reference I get into trouble.. Do I understand you correctly, that (assuming your WB is manual and thus consistent) I should be able to apply my color correction to every shot I did and it should work mostly out of the box?

    It really depends on what you're doing. The continuity of your source clips will determine the difficulty of attaining a consistent grade. One 3D LUT is really not going to cut it in a commercial setting, but maybe it will work for solo stuff under the same single camera setting and lighting conditions. 

  13. I've gone through lots of RAID nightmares and I'd say just go for the max speed and space, i.e. level 0, and then as stated above: use hardware to manage. Then backup to tape often or nightly. I also don't keep project files on RAID, I just us it for source footage (which always exists somewhere else as a master), renders and cache, but keep all project files on internal SATA. I think RAID is still useful for overall size and speed, but I would just forget about the redundancy benefits, rebuilding a RAID is something you never want to do. Then for backup I do nightly partial LTO backups with Bacula for RHEL, it uses MySql or Sqlite, is also available on Mac, Windows and Linux. Then I literally keep my archived LTO's in a fireproof go box... and I still can't sleep at night. 

  14. Define the tonal ranges in a clip

    The Luma Corrector, RGB Color Corrector, and Three-way Color Corrector effects let you define the tonal ranges for the shadows, midtones, and highlights so you can apply a color correction to a specific tonal range in an image. When used along with the Secondary Color Correction controls, defining a tonal range can help you apply adjustments to very specific elements in the image.

    • Select the clip you want to correct in a Timeline panel and apply either the Luma Corrector, RGB Color Corrector, or Three-way Color Corrector effect.
    • In the Effect Controls panel, click the triangle to expand the Luma Corrector, RGB Color Corrector, or Three-way Color Corrector effect.
    • Click the triangle to expand the Tonal Range Definition control.
       
      ap_14.png
      Tonal Range Definition control

      A. Shadow threshold B. Shadow softness C. Highlight softness D. Highlight threshold 
    • Drag the Shadow Threshold and Highlight Threshold sliders to define the shadow and highlight tonal ranges.

      It’s best if you make the adjustments while viewing the tritone Tonal Range display of the image.

    • Drag the Shadow Softness and Highlight Softness sliders to feather (soften) the boundaries between the tonal ranges.

      The amount of falloff depends on the image and how you want the color correction applied to it.

      Note:

      You can also define the tonal ranges by changing the numeric values or moving the sliders for the Shadow Threshold, Shadow Softness, Highlight Threshold, and Highlight Softness.

     

    This doesn't do it?

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