I took a series of macro shots that I wanted to use try my hand at focus stacking. Obviously the best way to do this would be to use a focus rail and tripod on a perfectly static subject, but since that's not always possible I decided to do a test under non-optimal conditions. I went ahead and took the shots of a flower handheld. The shots were nothing special but I've spent a few hours today just playing and trying to get my head around the process. I ran into some significant stumbling blocks and figured I'd see what others think about alternatives, workarounds, etc.
First off, I tried using CS4 since I already have it. I started with 6 16-bit TIFFs, ~24.6MP ea. System is an XP quad core 3.0 with 4G, lots of free HD space(~1.8TB) on my scratch drives. CS4 happily loaded the 16-bit TIFF files(6) into layers and auto-aligned them very well, considering the flower was swaying a bit. Unfortunately, when I tried to auto-blend the layers, CS4 ran out of RAM. After many experiments, restarting CS4(and XP) multiple times, etc. I found that auto-blend would work if I started with 8-bit TIFF or jpeg, cropped away the edges to where all images went to the edge of the canvas then reduced the image to 30%. Not especially encouraging, but it actually did a pretty nice job of blending it all together. Allowing CS4 to use more RAM, up to its maximum, didn't seem to help much.
I DL'ed a trial of Helicon focus and it swallowed up the 16-bit tiffs just fine but left a lot of artifacts around the edges, apparently due to movement. I tried exporting the CS4 layers as individual files after aligning and cropping, and ended up with slightly better results. I tried setting the alignment parameters up to 20 to see if maybe I had been limiting HF's ability to align, but it just crashed.
Tomorrow I'll try some captures for stacking using the bellows, since that's the only focus rail I have that's geared; I do have one on the way I can use without bellows.
So, question for the group, what have your experiences been with focus-stacking large files, with these tools or others?