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jackch2n

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  1. Like
    jackch2n reacted to anonim in Pocket 4K to Alexa Conversion   
    What a honest and noble behavior - not just to admit similar quality, but also to further explain it. Hat down, sir.
  2. Thanks
    jackch2n reacted to Sage in Pocket 4K to Alexa Conversion   
    He has done an excellent job of matching color spaces solely using color tools. A 3x3 matrix is kind of like a uniform accordion of R,G & B space, the cleanest tool for the job. The unique advantages to this approach are its tweak-ability, and that it won't clip boundary data in Resolve if you place a grade before the powergrade (grade after though; preserve core logc)
  3. Like
    jackch2n reacted to Sage in Pocket 4K to Alexa Conversion   
    XT3 is in the plans, indeed. At this moment, its down to documenting the process of adding a camera to the server, and then streamlining the Pdf writing process as best I can (later today). This will make a camera cycle as efficient as possible.
    From the LogC alone, V4 isn't that different from V3 for the average image. When saturation becomes more extreme, V4 is quite a bit better (much, much more accurate to Alexa). And when using V4 on unintended formats (i.e. Rec709 footage), V4 holds up, while V3 doesn't. Here is a comparison with one of the more saturated images I've got (most notable shift), using Soft (most equivalent variation between 3 & 4):
    V3

    V4

  4. Like
    jackch2n reacted to Sage in Pocket 4K to Alexa Conversion   
    Attila does great work, he has an excellent grasp of the technical; highly recommended
    That 4K 60 sounds quite good (super-sampled 10 bit)
    Ironically, I've still been working away at the EC engine, and fixing copious bugs (its inevitable that when I think a thing is finished, the work has just begun ) That being said, I think today I've fully tested it, and everything is working really, really well.
    This is a GHa Tungsten LogC render from this morning; the wheels on the far left and right are completely theoretical extreme gamut, beyond what the camera can record - the ones in the center are actual log gamut (and V3 for comparison):
    V4:

    V3:

  5. Like
    jackch2n reacted to Sage in Pocket 4K to Alexa Conversion   
    The XT-3 likely has better; DR and gamut are interrelated (i.e. where r, g, and b clip). Sensor determines how much of both one can have. At ISO 400, the Alexa has more than the GH5 (more saturated, higher brightness clip point). The GH5 and P4K have rougher blue clipping (like Alexa red clipping under tungsten WB)
    The P4K has slightly less than the Alexa at 400, or including HR range, slightly more artifacted range. If image quality is primary, the P4K takes the cake (completely smooth codecs). The GH5 is best for its IBIS, or little things, like the viewfinder in sun. I intend to support the XT-3 directly this year, sooner rather than later.
  6. Like
    jackch2n reacted to Sage in Pocket 4K to Alexa Conversion   
    Very nice!
    From this morning, here is an interesting one. This is GHa Tun v4 extreme gamut finished with the new system (Tungsten extreme gamut is the most difficult scenario). GHa v4 Tun actually outperforms the Alexa in extreme red (Arri has the edge in blue though). Also note the slight banding apparent in blue/cyan/green (VLog All-I), a non-issue on the P4K  (GH5 on the bottom):
     

  7. Like
    jackch2n got a reaction from Sage in Pocket 4K to Alexa Conversion   
    The guides are included in the PDF guide provided.
  8. Like
    jackch2n got a reaction from RCV in Pocket 4K to Alexa Conversion   
    Thank you! The lens I used for the test shot with the girl holding the ColorChecker is Metabones 0.71x , YongNuo 50mm 1.8 and a Sankor 16D Anamorphic projector lens.
    The shot of the girl holding a picture frame in a room is from a test shot of my school assignment. The adjustments and the conversion I used is -1 Stop Pre Exp + P4Ka Tungsten (Main) + ABL 2 + Color Wheel Slider (Midtones and Highlights) to conform to cinema luminance for the skintone and scene context needed. Make sure to white balance to the key light and the skintone falls on the skintone line of the Vectorscope. 
  9. Thanks
    jackch2n got a reaction from RCV in Pocket 4K to Alexa Conversion   
    The guides are included in the PDF guide provided.
  10. Like
    jackch2n got a reaction from heart0less in Pocket 4K to Alexa Conversion   
    Thank you! The lens I used for the test shot with the girl holding the ColorChecker is Metabones 0.71x , YongNuo 50mm 1.8 and a Sankor 16D Anamorphic projector lens.
    The shot of the girl holding a picture frame in a room is from a test shot of my school assignment. The adjustments and the conversion I used is -1 Stop Pre Exp + P4Ka Tungsten (Main) + ABL 2 + Color Wheel Slider (Midtones and Highlights) to conform to cinema luminance for the skintone and scene context needed. Make sure to white balance to the key light and the skintone falls on the skintone line of the Vectorscope. 
  11. Like
    jackch2n reacted to Sage in Pocket 4K to Alexa Conversion   
    Happy New Year!
    Alexa has a distinctive red (when LogC is paired up with the intended display primaries). It is a deep magenta red, and twists moreso approaching extreme saturation. This can look stunning. Other cameras may opt for the default of twisting towards orange with increasing saturation because Cmos red clips to yellow, and the gamut clipping is more coherent. For example, the Alexa has an especially messy extreme red clipping at tungsten WB. With Gen 4, this extreme red behavior is simulated. Here is P4Ka v Alexa in extreme gamut, with EC709 (P4K at bottom):

    Apart from desired hue twists, like Arri display gamut, hue twists when conforming color spaces via interpolation (in log etc) have generally been one of the main challenges in developing EC (to keep the true clean hue lines as they should twist). At many stages, I've coded the engine to preserve clean hue lines. Hue is perceptually salient in color, and has a privileged place in the engine today (whereas once upon a time, it was just 'one of three' in the engine)
  12. Like
    jackch2n reacted to RCV in Pocket 4K to Alexa Conversion   
    This looks great. looking forward to seeing the video.  What lens is this?
     
    Looks incredible. Lighting and framinng. looking forward to the video. Im sure John Brawley is taking notice. BM should reach out to you to collaborate 
  13. Like
    jackch2n got a reaction from Sage in Pocket 4K to Alexa Conversion   
    Thanks Alex! That's great to hear.
  14. Thanks
    jackch2n reacted to Sage in Pocket 4K to Alexa Conversion   
    Very nice. Soon to put this one on the website -

    That's the plan. Today I finished a major engine rewrite, to greatly accelerate supporting new cameras. Its the most ambitious work yet, that self calibrates and auto iterates. It was enormously difficult, and I discovered legacy code mistakes dating back to the very beginning.
  15. Like
    jackch2n got a reaction from Sage in Pocket 4K to Alexa Conversion   
    Pre Exp -0.66 + P4Ka Daylight Main + ABL 3
  16. Like
    jackch2n got a reaction from mercer in Pocket 4K to Alexa Conversion   
    Pre Exp -0.66 + P4Ka Daylight Main + ABL 3
  17. Like
    jackch2n reacted to Sage in Pocket 4K to Alexa Conversion   
  18. Like
    jackch2n reacted to JeremyDulac in Pocket 4K to Alexa Conversion   
    That lut is literally not in the same universe as the level of work Alex has done here. I doubt that person profiled each camera - it looks more like hue curve adjustments in Resolve.
  19. Thanks
    jackch2n reacted to Sage in GH5 to Alexa Conversion   
    Thank's jackch2n; coming from GHa, you will find some new things - Exposure comps and ABLs, the Gradient Chart, Highlight Recovery/HDR regions, and Gen.4 color
  20. Thanks
    jackch2n got a reaction from Sage in GH5 to Alexa Conversion   
    Thanks Alex! Appreciate the effort you have done to make this color conversion. Can't wait to use it on my P4K's footages.
  21. Like
    jackch2n reacted to Sage in GH5 to Alexa Conversion   
    Its a sure thing that the S will be supported as an update to all 5 users. I made the classic error of making estimates based on projections of future productivity. This is something I've seen so often, I'm surprised I fell into it myself (I was one of those scarred by the 3K Scarlet experience, circa '08-'11, still waiting). I think smaller, independent manufacturers can fall into the trap of being too enthusiastic and optimistic about their own speed and potential.
    Something key to the picture is that the P4K, by virtue of its gamut and range, revealed limitations that I had missed with the GH5. It has been crucial in determining what the process to make the new HDR EC space would be. That process will directly be ported to the S and 5, and I think I will be able to do it much faster.
  22. Like
    jackch2n reacted to RCV in GH5 to Alexa Conversion   
    I am in agreement with you!!!
    I don't understand the rebellious-teen-diva-ish tone in some of the demands of this thread that the LUT be ready at their command.  They probably don't understand that Sage is  a one man R&D team, so he has to take his time to fine tune the luts. Plus as someone pointer earlier, updates are going to roll out soon and we don't know how that might affect the LUT as well.  Sage probably has other film demands to attend to, perhaps a full time job? He owes no one any deadline schedule. 
  23. Like
    jackch2n reacted to JeremyDulac in GH5 to Alexa Conversion   
    I mean the guy is only one person, and funding the camera rental, while nice, still doesn't pay the bills - which is where the time thing comes in, and Alex clearly has made a decision on what to do first based on the P4k demand. While that may not fit your needs, the Gh5s is becoming the minority, and I just think it is distasteful to act like he should just focus on what you want, because he said it is on the roadmap a long while back. He made no promises, and I am sure he has every intention of getting to it.
    I was simply throwing some sarcasm out there.
  24. Like
    jackch2n got a reaction from Sage in GH5 to Alexa Conversion   
    It's okay Alex. I can wait for the BMPCC 4K Conversion, just go with the flow and since the firmware 6.6 hasn't released and not sure when will BM release it, I'm afraid they will modify the color science or improve the Braw and this may impact the making of P4K Lut . Just take your time do your best.
  25. Like
    jackch2n reacted to Sage in GH5 to Alexa Conversion   
    Would never scrap it, I keep my word. The S is getting an update directly from the P4K variation - which is a lot better than V3 (gamut/smoothness/a certain new feature, its not just the P4K variation; its gen 4). Its taken a lot longer than I anticipated, as I had no idea how much it would improve (P4K, XT3, S1, Sony, all waiting). I am one person, working day and night, weekends included - and I won't stop until its done.
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