JI recently saw a tutorial on Exposure averaging vs HDR. I’m interested in trying this using Darktable if that’s possible.
Anybody had any experience with this?
the tutorial used Photoshop of course, but I run Linux and stick with Linux based processing programs.
Any ideas, insights?
Thanks!
G’MIC can average several shots. I don’t think this is something you can do with darktable.
See, for example, Pat David: mean
By Exposure averaging vs HDR I assume you are interested in blending images.
Because I have Hugin installed on my machine, I have enfuse available.
By putting the photographs I wish to blend into an empty folder, I can, in the terminal, cd to that folder and then enter “enfuse *.tif” (assuming it is tif’s you wish to blend). It runs fast and usually produces excellent results. (To be entered without the “”).
With Hugin available, images can be aligned in the terminal with “align_image_stack *.tif” (again assuming you are aligning tif’s).
Slightly more sophisticated:“align_image_stack -m -a OUT *.tif”
Where The -m switch will optimize the field of view for all images except the first.
The -a OUT will prefix all the output files as OUT…tif
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If you have a GPU (which is useful for darktable, too), you can use --gpu with align_image_stack to speed up the process even more.
Also check if your camera cannot do it for you, mine (EOS R) has an averaging multi-exposure mode, which directly gives you a single nice HDR raw file.
There is a lua script, image_stack.lua, that will do averaging.
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Thanks for the replies and my apology for the time it took to do so!
I need to do a bit more research. From what I understand so far, image averaging is different in some way to HDR. I will try some of the suggestions here, but I’d like to understand it a bit more.
The end result is increased dynamic range (signal-to-noise ratio). This is how Google’s HDR+ works fundamentally - underexpose all the frames to preserve highlights, then stack to get back the shadows.
See also this related discussion:
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The HDRmerge plugin let’s you select several different RAW files and combine them to form a single DNG (which you can then develop as normal). See here for more details
Ah I see, thanks for clarifying
thank you for all the replies! my apology for not being more involved with the discussion. Life got in the way…
I will investigate this further. Averaging is a bit different than HDR. What I find I will post.
Here is an article that best describes what I want to do. All of them point toward Lightroom and Photoshop as the tools used. Several images are exposed, and loaded as layers with different densities, then merged together.
I’ve only used Darktable as my PP workhorse, but don’t know it well enough to see if I can do this or not.
Any suggestions?? And thanks in advance!
GMIC or ImageMagick will do that for you. Of course, @patdavid has already written about it: Pat David: ImageMagick Average Blending Files
There is a lua script, called image stack, that let’s you do this in darktable. You can also choose different modes such as mean or average
Thank you for the suggestion
Where can I get this script? and will it run on Linux?
just googled it up: https://github.com/darktable-org/lua-scripts/blob/master/contrib/image_stack.lua
It runs on anything that has imagemagick (or graphicsmagick) installed 