Originally posted by Edgar_in_Indy Sure, you can get the meaning most of the time, but it makes it more of a chore to read than a pleasure. I love to pour over a good lens review, and this seems to be a very good one indeed.
I know someone posted that website here in the past, which is how I found it. As you said, the reviews are quite well done (aside from the language issues for us). There are a lot of other good Pentax comparisons on that site as well!
The bottom line I think is that no matter how good a lens is, none are perfect. They all seem to have drawbacks in some way or another, which, of course comes from their design. In almost all cases, for a lens to be good in one area, it has to give something up in another area, be it speed, focal range, size, weight, etc, etc. In the Sigma 30's case, it seems they gave up the corner sharpness at the fastest apertures when they designed it. If they tried to keep it sharp across the frame at f1.4-f5.6, who knows what other 'pros' they would have had to compromise. Likely the center sharpness right from f1.4 would have been one. I am anything but an expert in this, but for me, I just try and learn to play to my lens' strengths. If I want sharper corners for landscapes, etc., I know I will have to stop down to f8 or f11, and they will be just fine. It's the same reason I don't drag a lens like the 18-250 through the dirt. I realize they had to make design compromises to get that immense range into one fairly small lens. Again I just try and learn/remember to stop down to f8 to get better sharpness.