Originally posted by blackcloudbrew I own two DA* lenses (16-50 & 50-135) and a DA 17-70. All have SDM. I've had them for several years now. I had one failure of the 16-50 (not SDM related, it was a contact replacement), which was a $200 repair bill. These are my three best lenses and the get a lot of use. I get great image quality from them and I happen to like SDM. I don't shoot sports and don't do a lot of low light work. I've read a lot of the postings about SDM failure and sure, I'd like to see some solution or acknowledgment of it by Pentax but for me it all works and if it breaks I'll get it fixed, because what I get from these lenses is well worth the risk and potential cost.
Every time it's wet out and I want to shoot, I know which lenses I'm reaching for. Every time I'm doing a serious shoot, I know what lens I want on my camera and I have a lot of lenses to choose from too.
Down the road, I'll get a few more. I'm looking hard at the DA*55 now.
$0.02
I had the 16-50, and wasn't too impressed with it optically, but the 50-135 is a real winner. I'm always surprised at the images it produces - I've never had a zoom that made such sharp, contrasty images.
The Sigma 50-150 may be fast focusing, but it's not the lens the DA* 50-135 is. Not saying it's bad, at all; Just saying the 50-135 is something special. If it breaks, I'll get it fixed, and If I couldn't get it fixed, I would keep it and use it as a manual focus lens, it's that good.