Noise profile for Canon EOS T8i / 850D

[lphilpot]

For noise profiles, please also attach the entire archive with .pdf plots. darktable-noiseprofile-20220729.tar.gz

[rawfiner]

The profile looks good, thank you! I will integrate it in the coming weeks.

[lphilpot]

Dumb question, but once integrated and installed I can dispense with the "--noiseprofiles path" parameter I'm currently using, correct? Thanks.

[rawfiner]

Yes, you won't need the --noiseprofiles anymore. Sorry for the delay, I do not forget you, I am a bit busy these days...

[lphilpot]

No worries on the delay and thanks for the clarification. Appreciate your help.

[lphilpot]

One quick note...

It may be a misunderstanding on my part (?) but just in case there's something wrong with the profile (although you said it looks good) I want to mention this before it's integrated.

When I open an image in DT 4 / Windows 11 and activate denoise (profiled), the only profile I see is "generic poissonian". For example, the image is shot at ISO 320, I shot a profile image at ISO 320 and there's a line in the JSON file for ISO 320 (confirmed --noiseprofiles path is correct):

{"name": "EOS Rebel T8i iso 320", "iso": 320, "a": [1.96612206489124e-05, 8.46086964099575e-06, 1.63375098828191e-05], "b": [2.55025577870898e-08, 1.8442672449966e-08, 2.6567861200103e-08]},

So per the module docs I would expect to see a profile named something like "EOS Rebel T8i iso 320" but I don't. My camera maker and model are recognized elsewhere in DT, lens correction lists it exactly as above.

If I need to open an issue on this I'll be glad to, but just wanted to mention it first.

Thanks.

[rawfiner]

This can happen when there is a difference between the name of the camera that the noiseprofile script detected and put in the json file, and the name darktable sees when you open a raw file. Can you check it is written exactly the same way in both cases?

[kmilos]

I would guess the profile would have to go under the canonical "EOS 850D" name?

[lphilpot]

It appears to be correct.

darktable image information module model: EOS Rebel T8i maker: Canon ISO: 320

lens correction module (for example) Canon, EOS Rebel T8i

JSON file (excerpt)

  "noiseprofiles": [
    {
      "maker": "Canon",
      "models": [
        {
          "comment": "eos rebel t8i contributed by len",
          "model": "EOS Rebel T8i",
          "profiles": [

            ...

            {"name": "EOS Rebel T8i iso 320", "iso": 320, "a": [1.96612206489124e-05, 8.46086964099575e-06, 1.63375098828191e-05], "b": [2.55025577870898e-08, 1.8442672449966e-08, 2.6567861200103e-08]},

exiftool run against the RAW file, grepped out any references to name, maker, etc.

C:\data\images\Our-photos\_scratch>exiftool IMG_2550.CR3 | egrep -i "maker|model|Canon|T8i|850D"
MIME Type                       : image/x-canon-cr3
Major Brand                     : Canon Raw (.CRX)
Compressor Version              : CanonCR3_001/00.09.00/00.00.00
Make                            : Canon
Camera Model Name               : Canon EOS Rebel T8i
Canon Flash Mode                : Off
Canon Image Size                : n/a
Canon Exposure Mode             : Aperture-priority AE
Lens Type                       : Canon EF 28-80mm f/2.8-4L USM or Sigma Lens
Canon Image Type                : Canon EOS Rebel T8i
Canon Firmware Version          : Firmware Version 1.0.0
Canon Model ID                  : EOS Rebel T8i / 850D / X10i
Canon Image Width               : 6000
Canon Image Height              : 4000
Lens Model                      :
Color Data Version              : 19 (90D/850D/M6mkII/M200)

While the camera is named 850D outside the US (except in Japan), in this locale it's "T8i" so that looks right...

Thanks.

[lphilpot]

I can link to the raw file if desired.

[lphilpot]

Sorry for the multiple messages but just thought about this. I'm running Bill's nightly build 4.1.0+109~g4ea7e5d5c. I've not further upgraded due to several reports of issues with newer builds, although they're tapering off now.

[kmilos]

You'll have to dig into noise profile matching code to figure out if canonical name (850D) is used, or the alias (as read from exif).

[kmilos]

By the time we exchanged all these messages you could have tried the name change in the JSON file already...

[lphilpot]

I didn't realize it was simple as that. It matches on 850D and appears to work properly. The updated JSON is attached, if that works with the workflow here. If not, let me know where to send it.

Thanks. Canon_850D_noise_presets.zip

[rawfiner]

I can link to the raw file if desired.

Yes please. I will test and modify the json if needed when integrating. Thanks!

[lphilpot]

It's slightly too large to attach. Here's a zip file of the raw file: https://drive.google.com/file/d/1nykvpblZR7hyKONIt-eRMs8GpwSaiZCT/view?usp=sharing

Please let me know after you download and I'll delete it from my Google Drive.

Thanks.

[rawfiner]

I didn't realize it was simple as that. It matches on 850D and appears to work properly. The updated JSON is attached, if that works with the workflow here. If not, let me know where to send it.

Perfect thanks for the test!

Please let me know after you download and I'll delete it from my Google Drive.

I downloaded it

[lphilpot]

Thank you.