There you can find
1) DNG images from the camera
2) JPG images automatically generated by the camera (I use those to get exposure times from EXIF data)
3) TIF images obtained using the stage3 output of the Adobe DNG SDK
4) PPM images obtained using dcraw_emu.exe -W (which should be equivalent to what described in this comment https://www.libraw.org/comment/6511#comment-6511)
I like the TIF images because for half the exposure time I get half the pixel value, across the exposure range. The PPM images are not predictable, which implies that some extra processing is happening. Please see the original attachment for a plot of image average (across all pixels, all channels) VS exposure time.
Sorry, I didn’t realize right away that I was already talking with two people.
Could you please formulate your problem not referring to the 'OP'. Also, it would be great to have RAW file(s) in question еo discuss something in specific detail and not in the abstract.
Auto-ETTR is performed on output stage, while converting from linear internal representation to gamma-corrected output in LibRaw::write_tiff_ppm or LibRaw::copy_mem_image
Thanks. I tried different combinations of the options in the list you linked, but no luck.
Can you point me to where I can access settings for Auto-ETTR in the source code?
You can find an example dataset here https://drive.google.com/drive/folders/1X4Cqj-hhLXOktWsfFN4e2yfWWZI5BGHK...
There you can find
1) DNG images from the camera
2) JPG images automatically generated by the camera (I use those to get exposure times from EXIF data)
3) TIF images obtained using the stage3 output of the Adobe DNG SDK
4) PPM images obtained using dcraw_emu.exe -W (which should be equivalent to what described in this comment https://www.libraw.org/comment/6511#comment-6511)
I like the TIF images because for half the exposure time I get half the pixel value, across the exposure range. The PPM images are not predictable, which implies that some extra processing is happening. Please see the original attachment for a plot of image average (across all pixels, all channels) VS exposure time.
Sorry, I didn’t realize right away that I was already talking with two people.
Could you please formulate your problem not referring to the 'OP'. Also, it would be great to have RAW file(s) in question еo discuss something in specific detail and not in the abstract.
Original post, here https://www.libraw.org/node/2740
He uses -W which is no_auto_bright but has that issue
Sorry, what is 'OP' ?
This creates images like in the OP, with unpredictable gamma.
Yes, this should(*) turn off auto-ETTR/auto-scaling, so this will result into dark(er) images.
(*) we're not responsible for AndroidLibRaw so not absolutely sure set....() calls works as expected.
I use the unofficial Android port https://github.com/dburckh/AndroidLibRaw
which should apply the options:
no_auto_bright = true
no_auto_scale = true
Could you please clarify: you use LibRaw library from your application, or some LibRaw sample programs 'as is' (as a command-line utility)
I'm also struggling with this. Can you point out which command do I need to use to turn it off?
It was tagged while creating release files downloads for this site, export script works on tags.
Github release was created on your request
Great, thank you. It looks like you tagged it earlier today. I use the cmake repo for building so the missing configure is not a big deal.
Already tagged: https://github.com/LibRaw/LibRaw/tree/0.21.0
Official release is available via this site download section: https://www.libraw.org/download
Github release has been created too: https://github.com/LibRaw/LibRaw/releases/tag/0.21.0
(although github release does not contain generated ./configure script)
Auto-ETTR is performed on output stage, while converting from linear internal representation to gamma-corrected output in LibRaw::write_tiff_ppm or LibRaw::copy_mem_image
Thanks. I tried different combinations of the options in the list you linked, but no luck.
Can you point me to where I can access settings for Auto-ETTR in the source code?
rgb_cam is used to construct camera to output RGB matrix: https://github.com/LibRaw/LibRaw/blob/master/src/postprocessing/postproc...
Cmatrix is the same, it may be copied to rgb_cam if corresponding params option is set and the matrix is not empty: https://github.com/LibRaw/LibRaw/blob/master/src/metadata/identify.cpp#L...
Spot on! 0-21 works perfectly.
Thanks!
Could you use a more recent LibRaw version?
https://www.libraw.org/news/libraw-0-21
You can run dcraw_emu without parameters, and also have a look at https://www.libraw.org/docs/Samples-LibRaw.html
On a side note, exposure is measured in lux seconds.
anything I can do via options in the binaries? Any pointers on where to start would be great. Thanks.
dcraw (and, so, LibRaw) standard processing is 'auto-ETTR', there are a lot of option to change it.
Does your software vendor tell you that your camera isn't supported because of LibRaw?
If so, have they tried to contact us?
> I’m assuming the next snapshot will add support for recently released cameras like Fuji X-T5, X-H2, Sony A7R5, etc
Please don't assume.
Sure, at our News section of this site.
For example: https://www.libraw.org/news/libraw-0-21
Are the release notes publicly accessible and do they offer a list of camera updates, by chance?
We plan to release 0.21-release this month.
Public snapshots are published every 7-9 months: https://www.libraw.org/#updatepolicy
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