Following a recent suggestion from @Elle Stone, and thanks to her help, I have managed to create a script that blends multiple exposures into a low-noise, high dynamic range image, pretty much like Guillermo’s ZeroNoise and HDRMerge… with few important differences:
- the various bracketed exposures are individually processed and converted to 16-bit TIFFs using PhotoFlow’s batch processor. In this step, one can already correct the lens distortions, which helps the subsequent alignment and merging of the shots
- the TIFFs are then aligned using Hugin’s align_image_stack
- the aligned images are then included into an auto-generated .PFI file that provides all the required exposure compensations and luminosity masks in the form of non-destructive layers
One advantage of this approach is that once the final .PFI file is opened, all aspects of the exposure blending can still be tweaked. For example, it is possible to modify the blending masks in order to manually remove ghosting due to moving objects. It is also possible to tweak the exposure compensation of each image in the case that the auto-generated values are not precise enough.
Finally, the .PFI file can be directly opened in GIMP via the PhF plug-in.
Here is an example of a five-stops bracketed sequence merged with the script:
Here is a detail of the darkest frame, overexposed by 6 stops:
and here is the same over-exposed detail, this time using the blended low-noise version:
The script requires an experimental branch of PhotoFlow, that includes additional code for proper handling of linear-gamma and high-dynamic range images.
If anybody is interested, I can provide more details and instructions on how to install and use this tool…