Originally posted by Kunzite Ughh... normhead, did you just called Pentax "a relatively inexperienced big glass designer on his first effort"? Did you ask "how far has Pentax fallen"?
Please tell me it was only my imagination... no way you'd say such things about the company designing 645 lenses and the two big zooms - not to mention their heritage lenses, which are not all small (compared to the same-era lenses).
OK then, show me the Pentax 50 before this one that were anywhere near this size. The 55 1.4 is 375 grams. Hardly huge compared to the Sigma 50 1.4 referenced above. In fact, still relatively small. You say Pentax has experience producing huge lenses in traditional focal lengths. Your example please?
This is not about producing big lenses as in a 645 or telephoto. This is about taking traditionally compact designs like the 50, and adding many new elements to help control CA, which is a proposition of debatable value when looking at various images. Digitalis' comparison of the Sigma 30 1.4 rendering pretty close to the 31 ltd, with the 31 having much smoother bokeh at the higher f values. The big glass was a trade off, not a straight up improvement. People seem to be jumping to he conclusion that because it's bigger and more corrected, that they will render better looking images, and so far that has not been established. You could look at the 31 and Sigma 30 and pick either one depending on your preferences. I'd pick the 31. Others have flat out said they prefer the Sigma.
So the big thing here is that the bigger lenses currently being designed may or may not be judged as superior or inferior by any given individual. Until we see the lens and how it renders we won't have a valid opinion. The 28-105 gives us hope, it's a great lens for the money... but it's a compact design, not a big heavily corrected design. And while the 70-200 and 150-450 get a lot of love from the Pentax community, no one is changing systems to get them. They might be as good as the competition, but there's been little indication whether or not that's true one way or the other, even though they've added quite a bit of weight. As I said, Pentax hasn't done this before, and it hasn't.