Originally posted by Biro I have the Pentax 12-24mm. Currently I'm thinking about picking up either the Pentax 10-17mm fisheye or the Samyang 8mm fisheye. But I wonder if this Sigma might be the way to go. I wonder if it's different enough from the 12-24 to be worth it.
Personally, I would get the DA10-17 if you already have the 12-24 and like it. It is wider @ 10mm than the 8-16 @ 8mm, even after de-fishing in Lightroom's lens profile, and *much* wider uncorrected. The fisheye perspective gives you different creative options given that you already have an extremely wide rectilinear lens.
I had the 8-16 for a month, and really liked it. Images from that month can be seen
HERE. I just love my DA10-17 and DA15 more, and couldn't justify keeping another big lens.