Originally posted by ogl The problem of almost 90% of first DA15 is decentered.
All photos which I saw say the same and Dpreview says
Our test sample was also slightly decentered too
Low quality control?
If you paid attention to Klaus at photozone you would end up believing all WA from any brand are slightly to severely decentered. A perfectly centered lens is rare...
Not to mention in lens SR is by definition decentering....
EDIT: Since telling the truth is a sure way to get yourself a fanboy title I guess I'm guilty.. It's tough when you actually go out of the box and see the other side and realize it's all pretty much the same...... not that some Pentax issues may be more than others in certain areas... see I said it out loud!!! Heavens
how about Erwin Puts (warning more reality ahead)
All this sophisticated equipment and statistically controlled computer analysis can not guarantee that the results are relevant for two reasons: the camera is still manually aligned in front of the test board and here we see a remarkable phenomenon: the results for decentring of a lens are impossibly high: they find on average a decentring between 8% and 15%. This is measured as the difference between the performances measured at the edges of the image. But it is almost impossible by visual inspection to align a camera absolutely plane parallel in front of a test plane. This observation is not intended as critique: I think the people at Image Engineering do an excellent job. This story is only told here to give an indication of how easily it is to make errors in testing and how large the effort has to be to control the inevitable tolerances in test equipment and procedures.
The second problem is the manufacturing process: however good a company and is quality control, there has to be some allowance for manufacturing tolerances. A margin of plus/minus 5% is really excellent in consumer electronic products and cameras. Tolerances