Originally posted by Tbear Ever since I learned of the development of the DA* lens series I was very excited about the prospect of owning one. Then I saw just too many negative threads and examples of problems with this lens. There was talk of QC problems in the Vietnam factory that makes this lens. So I decided to wait a few months for some of the kinks to be worked out. Recently, I have read more positive reports on this lens than negative so I figured it was time to pull the trigger. I bought my non-gray market, brand new, USA warranty DA*16-50mm lens from a major, very reputable online retailer. The lens arrived today and with hopefulness I immediately put it to a newspaper test against my kit lens (DA 18-55mm). This was using a K10D, SLIK PRO 700 DX tripod (rated for 15lbs) with SR off and 2 second delay with mirror up. I tried to compare apples with apples by using matching focal lengths and apertures (e.g. 18mm at f/3.5, 31mm at f/4, etc). Tripod, camera and newspaper positions as well as lighting were identical in making the comparison. Images were opened in Lightroom 1.3 and compared side by side. The bottom line: The * lens had terrible sharpness on the left side of all images, being most pronounced at 31mm! The kit lens demonstrated good sharpness that was consistent across the newspaper. I could not discern any difference in sharpness between the left and right edges with the kit lens. I include the 31mm f/4 images from both lenses (these were converted from PEF to about 4MB JPEG files, so the findings are not nearly as obvious as with the RAW images):
Kit lens at 31mm f/4:
http://farm3.static.flickr.com/2223/2164069842_c9cff5b1e0_b.jpg
DA* 16-50mm at 31mm f/4:
http://farm3.static.flickr.com/2087/2164053600_cf05e485dc_b.jpg
Immediately upon reviewing the results in Lightroom on my monitor, I contacted Pentax Customer Support. They told me they were unaware of any QC issues with this lens or with their Vietnam factory. I have FedExed the lens to Pentax USA at my expense in Westminster, CO where they will repair or replace the lens as they see fit. I am hopeful that Pentax will resolve this matter favorably for me.
TBear,
Rest assured..... Pentax WILL fix or replace the lens for you. They clearly are aware that there were defective batches early on and that some of these may still be circulating. I had one of the first DA*16-50's on the market and it showed chronic decentering especially at the wider end.
Pentax clearly agreed and sent a new custom calibrated lens to me at their expense.
Pentax customer support is not bad. In the end you will get the lens you were hoping for from them. It will still be a little weak on the wider 16mm end, but it shines mightily from 20mm on. Color and contrast are truly superb. I still use the lens at 16mm, but would select the DA12-24 for my wider shots.... where I personally think it excels.
Keep your chin up and breath deep. You made the right choice, just got a bad copy.
The new one should work out well.
Stephen