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Forum: Pentax K-5 & K-5 II
10-24-2011, 08:13 PM
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I have had the DA* 16-50 and 50-135 since the first time I could get my hands on them somewhere near the second batch that hit the US or so.
My 16-50 failed within the warranty period and would not focus. It was replaced, not repaired, and has never had a problem since then. Note that it is on one of my Pentax bodies almost all the time.
The 50-135 has not failed, but it does sometimes squeak, which is often a pre-cursor to SDM failure. It gets far less use.
No one here has any way of knowing if there has been any running changes to the design or to the specifications of the SDM motor to address these problems and we also have no way of knowing whether the current failure rate is better or worse than earlier.
The 16-50 is good, but not great optically (especially at the wide end wide open) but the 50-135 is just excellent.
I would not hesitate to buy them both again. If they fail during warranty, send them to be fixed. If they fail after warranty, pay to get them fixed or try the DIY SDM screw adjustment fix. If you can get a good extended warranty, that probably would be a good idea.
Lastly, it does seem quite silly that Pentax never issued a simple firmware update to allow screw-drive use of these lenses in the case of SDM failure. The lack of noise with SDM is nice, but knowing the lens will not let you down in a critical shoot and become completely useless seems to be perfectly in keeping with the intent of DA* lenses and a camera like the K5. After all, they are WR and have quick-shift manual focus, why not back-up screw-drive?
Maybe we should get Adam to contact Ricoh about getting this feature added to address the never-ending fear about buying SDM from Ricoh/Pentax.
Ray
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