Originally posted by Stavri I wasn't being sarcastic at all. There's a lot for work that goes into making lenses, formula, coating, polishing, gluing, aligning etc. Pentax lenses have usually higher T/stops then 3rd party products. Next time you look at the Sigma EX (high performance) line and wonder why the OOF renders the way it does (astigmatism, sub-par polishing or optical flaws) you understand why you got it for 1/2 off...
I think that while we do agree there is a difference, the question is, is it worth 100% more, just to get the subtle improvement in bokeh or whatnot? For most folks, no. They care about sharpness, price, and not much else. Which is why lenses like the Sigma Art primes are doing so well. They may not have the "character" of a Canon L prime or a Leica lens, but they get the job done, very sharply, and they don't cost much at all.
I guess your point was that Tokina couldn't have possibly designed a 24-70 with ALL of the optical prowess of a Canon / Nikon / Pentax lens, and in my opinion I suspect that you'd be correct about some aspects of image quality, but incorrect about others. Tokina may be a champ in the department of wide-angle sharpness, (They seem to be able to do no wrong; I've tested the 12-24, 11-16, 12-28, 11-20, and 16-28) ...they do indeed fall short sometimes, especially with their older lenses, in terms of bokeh, flare, distortion, etc.
However, lately I have indeed seen great improvements in these areas from Tokina, Tamron, and Sigma alike. They still have a ways to go, but they do seem to be eliminating many of their individual shortcomings of the past, and they're not charging $2K for it either. That was my point, I think.
Personally for astro-landscape work, I do indeed care about things such as coma, field curvature, and light falloff, which is why I often find that some third party lenses fall short. Others, however, do deliver "the goods"...
=Matt=