thank you. what is that olympus 520 8mm one you have there that is much more narrow?
what did you use to defish?
...couldn't you EASILY live without the 12-24?
The Olympus is a 9-18mm lens, set at 9mm. But Olympus is a 2x crop-factor camera (unlike the 1.6 for Canon crop DSLRs), so the full-frame equiv is 18 (2 x 9) for that lens (the Tokina 12-24 is a 19.2 equiv on the Canon camera). Also, Olympus cameras have a different aspect ratio than Canon. Olympus is a 4:3 ratio, so the images are taller and not as wide.
I used PaintShop Pro version X4 to defish. It has some options, like the percent of defishing, and a checkbox that adjusts how it adjusts the center, which sounds kind of like what you said that plug-in product has.
Yes, I suppose I could get by without the 12-24, if I'd bought the fisheye lens first (I got the 12-24 first). It's a good idea, especially since ultra-wides are so terribly expensive.