I’ve merged 3 brackets; -2EV, 0, +2EV. HDRMerge has used the +2EV as a based line (less noisy). The sky is obviously blown out and the merging uses the 0EV bracket (the -2EV hasn’t been used).
I haven’t removed any pixels; I’ve left the default merging. Then saved it to 24 bits and in RawTherapee the recovered sky is displayed in pink.
If I open the 0EV or the -2EV raw files in RawTherapee; there is no blown highlight.
@anubis I tried hdrmerge with your images. One problem with your files is, that there is no information about aperture in exif. This leads to some NAN values in processing the files. The aperture value normally is used to identify the EV of the raw files (there are cameras which change aperture while bracketing). But for your case (no aperture value or aperture 0) I can try to use a dummy value (2.8 for example) instead. I’ll create an issue and see what I can do tomorrow. Today it’s still too hot here in Germany to do serious work…
If the aperture is constant for all raws of the merge, its value shouldn’t play a role (with the exception of aperture 0 in your case, which seems to lead to division by zero). Unfortunately Canon cams don’t allow to set the aperture (even max aperture would be useful) for manual lenses. I understand that it’s not possible for Canon cameras to store the current aperture in exif when using manual lenses, but storing the max aperture maybe would be possible technically and probably help in this case.