Originally posted by thejediknight What lenses would you suggest as similar lenses (with the same good optical quality) if I didn't go for the DAs?
I would suggest looking at the Tamron 17-50/2.8 as a possible alternative to the DA*16-50/2.8. You could also try the Tamron 70-200/2.8 instead of the DA*50-135, but obviously the focal length is shifted a bit. Sigma used to make a 50-150 that seems to get a lot of praise. I've never owned one, so I can't say for certain if the IQ is as good as the DA*, but I suspect it's not too far off.
Originally posted by thejediknight Most of the complaints about SDM failures seem to be from 2007-2009. Are the new lenses from 2009-2010 failing as well? I am hoping that maybe Pentax fixed the QA/design issues in the recent lenses?
There is no reason to believe there has been any design change that addressed the issue. There is speculation, but I believe it is unfounded. Whether Pentax's QA/QC got any better would just be a guess, although again I have no reason to believe it did.
Originally posted by thejediknight Does anyone know if Pentax officially acknowledged fixing these issues?
No, they have not acknowledged anything as far as I know.
Originally posted by thejediknight Thanks!
You're welcome
Now despite my answers above, I really like my DA* lenses, especially the 50-135. I realize the SDM motor is the weak link in their design, but I also try not to worry about it either. There's are a ton of threads which talk about the issue, so I would recommend doing a little more reading on the subject and then coming to your own conclusion about whether or not buying a DA* lens is right for you based on the risk, IQ, cost, etc.