http://www.pentaxforums.com/userreviews/showproduct.php?product=377&cat=74
Fengwei, the link already was provided
Here you are the review, up against the DA*200mm f2.8 prime len from the above, but what I saw on gigahz 50-135 was stark sharp and nice bokeh. They claimed that the Sigma could be called a Pentax star len for a Sigma 70-200 F2.8.
volosong
Site Supporter
Registered: September 2006
Location: Laurentia
Posts: 431 Review Date: Tue April 29, 2008 Would you recommend the lens? Yes | How much did it cost? (U.S. Dollars): $739.95 | Rating: 10
Pros: optical quality, mechanical construction
Cons: absolutely none
If on the side of the barrel this lens said "Pentax" instead of "Sigma", it would be a FA* lens. It it THAT good! It is so good that I'm having a hard time convincing myself that I want or need the DA* 200/2.8 lens. This one covers the same exact focal length and maximum aperture.
My copy is the pre-DG version. Even though it is the older screw drive autofocus mechanism, it is focusing very quickly. Only in the dimmest of light conditions does it hunt for focus, but which lens on a Pentax body doesn't.
This is my go-to lens when I shoot sports. It also works flawlessly with the Sigma EX teleconverters. With the EX 1.4x converter, you have a 98-280/4 lens. You may ask yourself that with this combination, why do I need the Sigma EX 100-300/4? Truly, you will really question. You will not be giving up much.
Price paid was in May of 2005 from Sigma4less and reflects availability and market at that time.