Klaus Schroiff's K10D Review at PhotoZone

Klaus Schroiff, site owner and editor of the PhotoZone, recently has published his K10D full review and test report:-

http://www.photozone.de/8Reviews/dslr/pentax_k10d/index.html

I highly recommend to read this report of Klaus's (also for his other reports, without any hesitation) as his findings and conclusions are sensible and insightful, most importantly, comments and conclusions are usually made with good enough technical grounds and evidences. Nevertheless, his report is yet concise and easy to read. Of course, some of his particular conclusions and viewpoints made can still be subjective somehow but then this is of no difference from any other reviewers. At least, his tests and reviews are in a comparatively higher standard class of only few truly quality reviews belong to, amongst all other numerous sub-standard so-so "reviews" floating around the net.

Well, in Klaus's test report, he has actually reported something new, of which these new findings have never been reported by anyone so specifically before.

One of his new findings is about the obvious differences in resolution and the appearance of moires, etc. along the vertical versus the horizontal directions. With this strange and unique behaviour which I have reported here previously, Klaus did consider that it's simply a design flaw when he first saw the symptom. Later on Klaus was able to find out the possible cause to this problem, which is believed to be caused by the unequal strength of the Anti-Aliasing (AA) filter in the vertical and horizontal directions, more specifically: In the vertical direction, the AA filtering is much weaker than normal (i.e., very little dispersion to none, microscopically). And, in the horizontal direction, the AA filtering is yet stronger than typical (i.e., more dispersion).

Well, if we read into the details presented by Klaus. We can see that neither a too weak nor a too strong AA filter is good for the final image quality. Too weak a filter will create colour moires and very visible Bayer artifacts. Too strong a filter will decrease resolution significantly and blur the image too much.

It is found that Pentax takes the approach of using software (no matter it is in-camera or not) to do the demosaic job, as a remedial to the weak AA filter, vertically, which unfortunately just create even more blur and resulting in more loss in resolution. If 3rd party RAW convertors are used to convert the images, it can be seen that more serious and obvious colour moires will appear, although more resolution can be retrieved, also this will generate more noises too (see in the report for the noise level comparison by different convertors).

On the other hand, for the horizontal run, the image quality suffers from another extreme. So, this asymmetrical design of the AA filter, simply cause much undesirable effects which, however, cannot be handled by any RAW convertor with any software algorithm. In the end, one must see either more colour moires with better resolution (about vertically) or an image with less colour moires and noises but with inferior resolution and obvious blur.

The worst thing IMO is that the images will always look somehow different in vertical run against horizontally. I just wonder why Pentax need to design and make a camera in this way, of which this design and the produced results are indeed very strange and the image quality suffers and that no other DSLR makers else have ever done so, nor Pentax themselves for their previous models.

BTW, as we all know, the selling point of a 10MP+ DSLR is its higher resolution, however, the K10D by itself simply fails to deliver, no matter shooting in Jpeg or RAW, if only Pentax software is used. If one uses 3rd party RAW convertors, more moires and noises are resulted. Even worse, do note again that these are not symmetrical vertically and horzontally.

Whilst Klaus finally mentions this strange problem, which was actually first reported by him, is just a "Minor Con" in his final test report conclusion, I must regard this problem to be a *Major* Con, as this affects the image quality seriously and especially there is NO true solution to this killing problem.

Also, as for the "phantom" bright and dark pixels revealed under pixel peeping, it is actually a mystery to Klaus and all of us.

Finally, if you read back Phil Askey's K10D review, we can now all know why Phil Askey found the problem of "soft edged images" (in-camera Jpegs or RAW converted images via Pentax PhotoLab, same here for what Klaus has found), which led to a low rating in the image quality part of the DPR review. Well, now Klaus's latest findings and explanations have indeed given full answers to the questions raised by Phil Askey, of which there was no brief answer at all even by Phil Askey himself in his DPR K10D review. In fact, Phil Askey actually did not describe the problem as clear and as specific as what Klaus has achieved - Phil Askey just wondered and puzzled for the odds he saw and then he just (told us that he) "scratched his head hard". So, afterall, I think we must thank Klaus for letting us and all Pentaxians finally know the answers to this mystery! :-) My big smile to him and thumb up!