Converting CHDK RAW files to something DXO PhotoLab 2 will read

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Converting CHDK RAW files to something DXO PhotoLab 2 will read
« on: 29 / November / 2018, 16:09:00 »
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Having just bought this on the basis of what it could do with RAW files from my Sony DSLRs, I am a bit disappointed to discover that it doesn't seem to like ones generated by CHDK.

It will read: .CR2 files from a Powershot S95 running Canon's firmware :)

It won't read: .CRW files or .DNG from CHDK from the S95 or Powershot S100 :(

(By the point I got the S100, I was enough of a CHDK convert that I don't think I have any Canon firmware photos from it yet!)

A quick look at what else I have shows that Corel AfterShot Pro 3 also doesn't like either of the CHDK ones, but darktable will read the .DNGs.

Is there any way to convert them into something it will read (.CR2 or ???)

I can find plenty of ways to go from the .CR? to .DNG, but not the other way round...



Re: Converting CHDK RAW files to something DXO PhotoLab 2 will read
« Reply #1 on: 29 / November / 2018, 17:15:20 »
Oops, just remembered to try RawTherapee - it will do the .CR2, but not the .CRW and does .DNG badly (perhaps related to the bug mentioned elsewhere here?)

Trying with more of them PhotoLab 2 will do a much better job with the most recent .DNG - early ones have a very strong magenta cast. For some reason it improves greatly between shots taken on the same day earlier this month - two have the magenta cast, one doesn't - and ones taken last weekend are great. I will have updated the CHDK version at some point, but I'm (reasonably) sure it wasn't between those three photos.

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Offline reyalp

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Re: Converting CHDK RAW files to something DXO PhotoLab 2 will read
« Reply #2 on: 29 / November / 2018, 23:18:07 »
Oops, just remembered to try RawTherapee - it will do the .CR2, but not the .CRW and does .DNG badly
Generally, you'll find that software supports Canon raw much better out of the box than CHDK files. If your camera has Canon raw and your software handles it well, use it. It generally shoots a bit faster than CHDK raw/DNG too.

CHDK .CRW isn't in CRW format, it's just a frame buffer dump without any metadata. It is strongly recommended that you use DNG instead.

DNG compatible software should load CHDK DNGs, but the default rendering probably won't be as pretty as Canon raw. You should be able to get results equivalent to Canon raw with appropriate settings, lens correction and so on.

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(perhaps related to the bug mentioned elsewhere here?)
It would be helpful if you referenced the specific bug, there a lot to choose from ;)

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Trying with more of them PhotoLab 2 will do a much better job with the most recent .DNG - early ones have a very strong magenta cast. For some reason it improves greatly between shots taken on the same day earlier this month - two have the magenta cast, one doesn't - and ones taken last weekend are great.
IMO, the difference almost certainly has to do with the scene and exposure, not the day. Many programs apply a contrast stretch to raw images, which can go wildly wrong in some cases. This is particularly common when large areas of the image should be dark. Some versions of raw therapee do this by default. Pressing the "reset" or "neutral" button on the exposure tab should get you to default settings. The default settings will probably look very dull compared to canon jpeg colors.

If you upload examples of your good and bad DNGs somewhere (they are too large for the forum, use google drive, dropbox etc), I can take a look.

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I will have updated the CHDK version at some point, but I'm (reasonably) sure it wasn't between those three photos.
There haven't been any changes that should affect the look of raw files in a long time.
Don't forget what the H stands for.

 

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