Thanks for the info. I already had the 15-30 to use with my SD10, and have the SD14 as of a year ago. While that was a decent angle of view, I needed an extreme angle. I found an SA9 in mint shape (except for the yellowing finder) for $95 on ebay with an inexpensive 28-105 lens. Back about 6 months ago I managed to snag another SA9 with a 70-300 lens, a 24-70 lens, and another Sigma 500 Super flash for $70. I figure I got the flash for a decent price and they threw the rest of the gear in for free
Anyway, that's when I figured out the yellowing viewfinders were an endemic problem with the SA cameras. I have had my eye on the 10-20 zoom and would probably get that, unless the 8-16 drops in price some. In the meantime, the few times I need the extra width, I just use the film camera with the 15-30 lens on it. Consider the application; I take a shot of an exhibit tent that is 10 feet square and need to be in close enough that the sides are visible and clearly show the framed photos hanging on the side wall. The 15mm setting on the Sd cameras just gets the job done, but on the film body it opens up very nicely. A little work in PS clears up the spherical aberrations and the perspective alignment from the camera position against the straight edges of the walls.
Given my choice, I would like that 8-16 but I've got to justify the expense right now. It's on the wish list