Should I merge the bracketed images into a 32 bit .HDR file, and then stitch?
Hi,
I'd say yes. The reason is that it avoids lots of unnecessary (and potentially error prone) registration errors, it also allows to first fix the Chromatic Aberrations and potential ghosting issues on individual shots before creating the HDRs. In addition, some not dedicated Pano stitchers cannot handle too many files because they run out of memory, although Autopano Giga should be able to cope. First assembling your HDRs, reduces the number of files to stitch to 1/3rd.
I was hoping to assemble a 32 bit HDR file then do the white balance, color adjustments, etc after the final image in stitched.
It depends on the type of Pano you're making.
When you cover a
very wide Field of View, it can help to process the individual tiles a bit differently. Although I usually do not shoot too wide, but rather increase resolution by using somewhat longer focal lengths and let the subject dictate the crop, I have shot 180-degree panos. Such an extreme Field of View means that part of the scene is front-lit, and part is back-lit.
Also, in a sunrise/sunset scene, part of the scene can have a warmer color balance (the front-lit by warm sunlight region) and the other part can have a cooler color balance (the cold back-lit shadows). That could make too much of a color balance shift in one image when printed in a smaller size. By gradually changing the color balance settings for the tiles going left to right, and adjusting the exposure some to compensate for illumination differences, the whole transition becomes more palatable.
The dedicated stitching software can make the (slight) differences between the tiles blend more gradually, although not all stitchers can handle that gracefully. I use PTGUI, which also allows using plugin blending engines in case those do a better job than the built-in blending.
Cheers,
Bart
