I recently took a sequence of shots at sunrise for the purpose of stitching. However, due to the contrast in the scene, every position in the sequence was also taken at 5 different exposures to allow me to use the manual HDR technique in which I layer the differently exposed files and then manually apply layer masks to get the precise effect I want. I do not want to use conventional HDR as I dislike how it looks and want to control it all.
My original intention had been to get PS separately to stitch together all of the files at a given exposure, layer those stitched files, then do the mask work at that point (i.e. on the layered set of stitched panorama files, each of which is at a different exposure). So, in other words, all the files taken at 1/125 would be stitched; so would all of those at 1/250 as a separate file, etc.; they would then be layered and align perfectly. Trouble is, due to the different detail visible in the files taken at different exposures, the stitching was not produced identically for the differently exposed shots. So the 1/125 stitched file did not match the shape and geometry of the 1/250 stitched file, etc. - which of course made simply layering those separate panoramas impossible, as they would not align.
So I then decided to do the laborious process of doing the layering and mask work on each set of identically framed (but differently exposed) shots, then flattening those files - to give a single sequence of shots that could be stitched. The trouble is getting those shots to have compatible density so that the stitching would work. That proved next to impossible. I could not simply match the opacity of the masks because the differently lit parts of the scene demanded different opacities of mask - but stitching them looked messy. The function within the stitching process that smooth out transitions still left banding/blotches, etc..
I can tidy all of that up, but it's a terribly slow and imperfect process.
What I would like to do is to find a way of forcing PS to do it the way I originally intended. In other words, to take one sequence of the shots all exposed the same, stitch them, then get PS to stitch the other sequences of shots identically, so that I can layer the identically aligned panoramas (which will have different exposures) and simply work on one set of masks. As I said above, normally stitching the differently exposed sets of files does NOT have this effect - presumably because the dark and light files lack the detail in parts of the scene to make the algorithms work in an identical way and you end up with quite different (and hence not aligned) stitched panoramas.
Does anyone have any ideas how to get PS, having stitched one set of files, to apply the EXACT same geometry to another set of files so they perfectly line up (given that the files at the different exposures are perfectly aligned)?
Hope this all makes sense!
BTW - I am using PS CS5 (in case that makes a difference).
Thanks in advance for any advice.