Chaos Corona Forum
Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: dj_buckley on 2017-11-27, 19:25:32
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Just wondering if anyone could advise how i'd go about extracting a response curve from my Nikon D810 and converting it to a LUT (or curve) that I can load in Corona Frame Buffer?
Or how to find out what the different picture profiles in my D810 are doing in terms of adjustments?
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Dubcat shows a useful method to extracting LUTs here for the frame buffer:
https://forum.corona-renderer.com/index.php?topic=12728.0
To answer your second question Dubcat has also provided a PSD file to see the adjustments to the curve your LUT is doing here:
https://forum.corona-renderer.com/index.php?topic=10306.0;all
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Perfect - cheers James - I also need a thread with a pinned post to links of all Dubcat's stuff :)
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haha, I have been saving his posts in my research bookmarks folder, lots more to understand but grinding away :)
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Just been through that post and can't see where it tells me how to extract a response curve from my camera. So the camera has different picture modes, but I want to see them in curve form.
I don't know how to get them from my camera to my PC in the first place
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when you say picture modes, are you referring to portrait, landscape, faithful, etc?
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Yeh - I'd love to know what they're doing curve wise. So basically my camera shoots RAW and JPEG as per any DSLR, if I choose JPEG, the output depends on what picture mode I have set - assuming I've not done any custom tuning that is. Am i mistaken that those picture modes as effectively different response curves?
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well as Dubcat explains in that link any adjustment you make to an image affects the curve of of that image (brightness,contrast, etc)
If you use a Canon Camera they are in this order (check the manual of your camera for specifics)
(http://i66.tinypic.com/29urnf7.jpg)
As I have tested shooting picture modes also affect the RAW - which is why I typically shoot in faithful (no colour additions) as I intend on adjusting in post
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For sure, I get that they adjust the curve, and that resulting curve is what I'm trying to extract.
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I see what you are looking for now. With jpeg obviously not its baked in, with the RAW files I can nudge you in the right direction as I want to do something similar myself but having some issues with getting the calibration to transfer the HALD file (as its a tif and not a raw file).
Hopefully someone with more experience can jump in here but from my understanding, you will need the HALD file and 3D Lut Creator to follow this method. If you watch the video you will see what I mean but still trying to get the technicals sorted. My thinking was if you can export the HALD to 3D Lut as a Mask, you can then export a LUT to use in your render:
Again if someone can jump in on this and give their 2cents I would really appreciate it - I also want to de-expose an image I took of my X-Rite Colour Checker (as its over exposed) and will not calibrate for a shoot I recently did. I can get it to match in 3D Lut Creator with a Log de-exposure but then I cannot export this as a DNG file. Any help on this would be appreciated, Im sure these 2 are closely related and could solve a few problems in one.
Edit: Update on this, I was able to get a good match using Adobes DNG Profile Editor.
I was also able to export the Camera Profiles (Faithful, Landscape, etc) to a DNG file. Im working through now how to convert these to a LUT.
Can I ask whats the intention? Could you shoot on raw and apply the colour/wb with a colour checker passport?
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The intention to be honest was to create a starting point for Corona Frame Buffer.
The camera is something I use regularly, so I'm used to seeing the screen on the back and how it looks with my chosen Picture Mode. So if could get the Frame Buffer working in a similar way to something I'm already familiar with and like, it would make getting my renders closer to what I want, much easier :)
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Just wondering if anyone could advise how i'd go about extracting a response curve from my Nikon D810 and converting it to a LUT (or curve) that I can load in Corona Frame Buffer?
Or how to find out what the different picture profiles in my D810 are doing in terms of adjustments?
Hey dj_buckley
Have you found a way to create a LUT from your camera response curve? If yes, please let me know how you did it.
I'm really interested in learning that process. Unfortunately I can't find any information about it. I know dubcat is doing it with a lot of camera models but no idea how he does it.