Originally posted by Groucho I don't see anyone mentioning the fact that Lightroom (and presumably ACR) can "correct" the Pentax 10-17mm into looking like a rectilinear UWA.
Fisheyes are very subjective. I love 'em, and by and large, I do *not* like UWA rectilinear shots. (I have absolutely no desire to own one of those 10-20mm, 12mm-24mm, etc UWA lenses.) The nice thing about the Pentax is that if you do like the UWA look, zooming out to 17mm gives you mostly that look with little fishiness, since the more curved edges are mostly cropped.
Unfortunately, the 10-17mm is definitely not perfect. There's a fair amount of purple fringing - which Lightroom can usually take care of pretty well - and the six aperture blades are a real bummer. Give me an odd number, or a minimum of eight if an even number - those six-pointed starbursts just aren't as impressive as the Nikon folks get with their 14-point starbursts from their 7-blade apertures.
My ultimate dream lens is the 10-17mm with some optical tweaking (cut back on the PF if possible - I know it's difficult being so wide), a nine-blade aperture, a little faster (F2.8 please), and weathersealing. That's what I want Pentax to make. The aperture blades would be the #1 thing on that list, weathersealing being #2.
I do still have my old Zenitar 16mm fisheye but really haven't used it since getting the 10-17mm... I just keep it around in case I want to shoot film or if Pentax does a FF and I end up buying one.
I never even try correcting in LR. To me, it just looks bad. When I bought my DA 10-17 several years ago, it was considerably cheaper than any of the other wide angle options available for Pentax. A lot of people bought them with the idea they could "de-fish" in PP. A lot of us soon got good deals on used 10-17's. It's a lens I always have along but I also carry a DA 15 in my bag. The DA 10-17 is a wonderful lens. It's very sharp and can focus very close but it's always a fisheye. It was designed to work that way and de-fishing looks far more distorted than the normal curved view it produces.
I generally use mine stopped down quite a bit so I don't really need a faster version. That would make it considerably larger and heavier too. The PF can be a problem sometimes as can flare. With such a large FOV, the sun always seems to get in there. I agree on the aperture blades. If this lens produced starbursts like the DA 15......well, I might not have bought the 15. When I bought mine back in 07 or 08, Amazon was selling this lens for $360. I got mine used for $300.