Color calibrating pixel shift images from A7RIV

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Jojakim Contributing Member • Posts: 538
Color calibrating pixel shift images from A7RIV

I've made color profiles with the free ColorChecker Camera Calibration application a few times now with good results. But somehow the application fails to work with pixel shift files from my A7R IV, saying 'Unable to open file. File is not a valid DNG file.'

It did work with a single shot photo, but as pixel shifting does increase the photo's color accuracy I figured it would be best to base the profile on a pixel shift photo as well.

Has anybody tried this as well? Perhaps the 240MP files are too much to chew on for the app?

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Sony a7R IV
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VLreviews
VLreviews Regular Member • Posts: 237
Re: Color calibrating pixel shift images from A7RIV
4

Have you tried to convert the files to DNG using pixelshift2dng?

https://www.fastrawviewer.com/PixelShift2DNG

It might produce different output than the Sony converter. Maybe those DNGs then work with your tool.

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OP Jojakim Contributing Member • Posts: 538
Re: Color calibrating pixel shift images from A7RIV

Thanks for the suggestion. But unfortunately I get the same error message with this DNG.

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Sony a7R IV
Entropy512 Veteran Member • Posts: 4,875
Re: Color calibrating pixel shift images from A7RIV
1

Jojakim wrote:

I've made color profiles with the free ColorChecker Camera Calibration application a few times now with good results. But somehow the application fails to work with pixel shift files from my A7R IV, saying 'Unable to open file. File is not a valid DNG file.'

It did work with a single shot photo, but as pixel shifting does increase the photo's color accuracy I figured it would be best to base the profile on a pixel shift photo as well.

Has anybody tried this as well? Perhaps the 240MP files are too much to chew on for the app?

I gave up on the ColorChecker app in favor of https://rawpedia.rawtherapee.com/How_to_create_DCP_color_profiles - the latter produces a better profile (more advanced than just two ColorMatrix entries, but additional LookTable color corrections) and also allows you to distortion correct the image (not super necessary for an A7-family camera, but was critical for a 360 camera with dual fisheye lenses)

Note that there are eventually going to be some enhancements to that workflow when I get more time to work on https://github.com/Beep6581/RawTherapee/issues/5575

Also, the A7R4's dynamic range is sufficient that you'll get little to no benefit from trying to make a color profile from a pixel shift image

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OP Jojakim Contributing Member • Posts: 538
Re: Color calibrating pixel shift images from A7RIV

Thanks so much for the hands on info.

I'm going to check out the RawTherapee profiling for sure.

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Sony a7R IV
Iliah Borg Forum Pro • Posts: 28,006
Re: Color calibrating pixel shift images from A7RIV
1

Jojakim wrote:

I've made color profiles with the free ColorChecker Camera Calibration application a few times now with good results. But somehow the application fails to work with pixel shift files from my A7R IV, saying 'Unable to open file. File is not a valid DNG file.'

It did work with a single shot photo, but as pixel shifting does increase the photo's color accuracy I figured it would be best to base the profile on a pixel shift photo as well.

Has anybody tried this as well? Perhaps the 240MP files are too much to chew on for the app?

ColorChecker doesn't have enough dynamic range for pixel shift to make a difference (given the target is exposed per X-Rite recommendations).

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