Thread: ACHTEL 9×7 Digital Cinema Camera: An “IMAX Mini” That Shoots 18.6K RAW

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  1. #21  
    Senior Member rand thompson's Avatar
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    Blair,

    I was trying to create a sequence from the DNG files but just the files of the redhead guy against the night scene is 21.5 GB . Plus the download never finishes.
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  2. #22  
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    Some more info https://nofilmschool.com/meet-65-meg...a-gunning-imax

    Also on the 18.7k resolution.
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  3. #23  
    Senior Member John Marchant's Avatar
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    Intrigued about the dynamic range claimed. The sensor manufacturer rates it at 11.6 stops.
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  4. #24  
    Senior Member rand thompson's Avatar
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    ACHTECH 9x7 digital camera DNxHR HQ file.


    By Rand Thompson

    Here's a 4096x3079 3 second DNxHR HQ file from the 180 DNG files for this clip, From 22GB to 482MB

    Edit:

    According to vimeo The download is 2874 × 2160 / 10.12MB. Even though I uploaded a 4096x3079/482MB file.


    download from Vimeo page
    https://vimeo.com/458786373

    Wetransfer

    482MB 4096x3079 DNxHR HQ file link, good for 7 days.
    https://we.tl/t-Ny5rYuSts8

    1.9GB 8192x6159 DNxHR HQ file link, good for 7 days.
    https://we.tl/t-X6mzRAjL3D

    Last edited by rand thompson; 09-16-2020 at 07:12 PM.
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  5. #25  
    Senior Member Karim D. Ghantous's Avatar
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    11.6 stops isn't too bad, if the trade-off is a global shutter. I guess it's the How, not the What.

    I keep saying that the future of cinema is IMAX. Instead of spending $100M on some superhero movie that nobody cares about 6 months later, why not spend $1M on a simple action/suspense/thriller where the camera looks down from tall buildings, and projectiles get fired at the camera? Then you get the bonus of spectacular establishing shots. That sort of effect, involving zero VFX, never gets old. I get acrophobia while playing Batman Arkham City on the Xbox 360. And I love it. That game is almost 10 years old.

    BTW I still want to know how they fucked up those JPEGs on the Website. Even if I tried I couldn't export JPEGs that bad. I've seen them from Red users and when I enquire, I get told that there's nothing wrong. Very frustrating. (Also why are we still using JPEGs in 2020 FFS? Progress!).
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  6. #26  
    Senior Member rand thompson's Avatar
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    Karim,

    There seem to be other trade-offs as well. If you add more gain to any of the night scene DNG files, you can see line patterns in the lighter areas, which is why I crushed the blacks in my grades a little more than normal. Also in some scenes there appeared to be some IR Polution, the girl at the beach scene for one example. In the original DNG Raw settings, there were high Kelvin settings,7979K, or very high Tint settings, -69.50 for some reason. Those values didn't seem to do anything to make the image look better so I don't know why they were chosen. I set the tint to zero, chose an appropriate kelvin setting, and graded from there.

    I use to upload .Tiff files to threads. However, It sometimes took way to long to load if they even finished loading at all. Plus, I guess jpegs are more universally usable than .Tiff, and they have faster transfer and download times than .Tiff, ,PNG or DPX files. Also some websites have limits on the size and resolutions of uploaded files.


    ungraded girl at the beach DNG file, seems like some IR Polution



    Last edited by rand thompson; 09-16-2020 at 09:49 PM.
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  7. #27  
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    The physics of large screen projection limit maximum photometric DR to 500:1 due to backlight scatter from the screen. That is 9 stops. The minimum SMPTE theatrical target is 150:1, which is 7 stops. 12 stops uncompressed DNG is pretty adequate if we are talking about conventional large screen projection plus the color gamut with well saturated Bayer filters can be phenomenal. Pawel mentions in one of his CML responses that digitizing more than 12 stops is just digitizing noise. He could be right.
    Below is an early sample frame from my Digital Bolex. It uses a 16 bit first stage AD with the four least significant bits truncated to produce a 12 bit CDNG file. 11.7 stops is the camera's effective DR. The scene metered a five stop middle gray spread between ambient shadow and direct sun with an incident meter so effectively representing about 15 stop scene DR under available light conditions with no artificial fill or reflectors involved. Linear CIE to REC709 2.4 gamma conversion in Resolve plus minor tweaks. Frankly I've not seen any samples from so called 13-14 stop DR cameras shooting log or compressed raw formats that render this depth of color, texture, and detail in deep shadow. Uncompressed DNG rocks!

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  8. #28  
    Senior Member Karim D. Ghantous's Avatar
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    Quote Originally Posted by rand thompson View Post
    I use to upload .Tiff files to threads. However, It sometimes took way to long to load if they even finished loading at all. Plus, I guess jpegs are more universally usable than .Tiff, and they have faster transfer and download times than .Tiff, ,PNG or DPX files. Also some websites have limits on the size and resolutions of uploaded files.
    I'm talking about JP2K or HEIF. All web browsers can read JP2K. I mean, for goodness sakes, we should have dispensed with JPEG 10 years ago.
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  9. #29  
    Senior Member rand thompson's Avatar
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    Quote Originally Posted by Karim D. Ghantous View Post
    I'm talking about JP2K or HEIF. All web browsers can read JP2K. I mean, for goodness sakes, we should have dispensed with JPEG 10 years ago.
    Oh, ok I see what you mean.
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  10. #30 Tech tangent 
    Senior Member Blair S. Paulsen's Avatar
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    Even with modern computing and data handling chops, uncompressed high resolution 16 bit imagery is a load. Particularly if each frame is its own file rather than part of a clip. My experiences with Cinema DNG have included some ridiculous off load times - as in coming back the next day and it's still not done. Smart, mild compression that supports manageable post operations with minimal quality loss can be a excellent alternative to the "uncompressed at all costs" approach. Mezzanine codecs at appropriate data rates rock.

    IMO, the hellscape is over-compression - particularly with a fixed maximum bitrate regardless of the material. Sadly, far too many content creators don't really understand how codecs work.

    Cheers - #19
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