Canon CR2 stills in ACES

canon
cr2
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(KirkThibault) #41

@soenke.heuer - also remember that white balance may affect the highlights. I got ok results with -H 2 and a WB performed on patch 4 of the last row. This WB is performed in rawtoaces using:

--wb-method 3 <x y w h>

where x and y are the coordinates of the upper left corner of the WB box and w and h are the width and height of the box. You can specify a box that includes pixels in a neutral patch to base your WB for rawtoaces libraw conversion.

I found that this method was ok, but produced WB that appeared and measured too blue. Give it a shot, see if it works any better with -H 2 in producing neutral highlights.

As Thomas already pointed out, at some point there is too little data in the blown channels to produce a reliable highlight reconstruction.

kirk


(Thomas Mansencal) #42

@soenke.heuer: The .exr file is here: https://mega.nz/#!wyRFWZ7J!uUGrQTBKPfccZjq8gEelBxCQLCax1ZT_5gCQu9P3Ae4.

“My tools” is Colour - HDRI, a Python package I created for image processing. It allows me to process images using different chains. For this particular one, it is converted to .dng for exif metadata normalisation, demosaiced using dcraw to linear CameraSpace 16-bit integer file, and then processed with Python for conversion to target colourspace, WB and highlights recovery.

I would not recommend using it, except if you know what you are doing: it is provided without battery, and even though used in production, it requires multi-processing wrappers to be efficient as it is slow. Let’s not derail the thread though :wink:

Thomas