Rick, in my (not really too humble) opinion, most of these tests are rubbish. I doubt that they are done in statistically correct manner (read: many scenes, many cameras, many lenses, etc). I also doubt their sense, as there doesn't seem to be involved any real life shooting, only special targets in controlled environment. Also, often you would end up in the situation like the one you described - confused, self-contrary, no real conclusion - helpless. From my experience, for example K-7 has at least (actually more) dynamic range than K10D. That would be in direct contradiction with DXOMark scoring. I cannot compare K-7 with K20D in low light having no K20D, but I don't think that K-7 will be significantly worse than K20D, as it would probably mean that Pentax engineering and marketing and management are all gone nuts.
I do believe however in asking people for their opinions, especially those people whose shooting style is somewhat similar to mine. I also believe in asking people to provide me with their real life pictures and looking at these pictures myself. To that end, I am perfectly willing to send you as many PEF's and DNG's as you'd like for evaluation of K-7 and/or K10D at any possible conditions, as long as I'd have these shots. HTH. On Mon, Jan 4, 2010 at 12:59 AM, Rick Womer <[email protected]> wrote: > Right now, I am not planning to replace my K10D with a K7, because the latter > does not seem to have significantly better low-light performance. By > reputation, the K20 is about 1 1/2 stops better than the K10 in low light, > and the K7 is about a half-stop worse than the K20 (thus a stop better than > the K10). > > That seemed simple, until I began looking into low-light performance test > results. > > The noise testing on dpreview used only jpgs until their review of the K7, > which compared RAW noise in the K7 and K20. For chroma noise, a score of 10 > (y-axis) corresponds to an ISO of about 2800 for the K20, and about 2000 for > the K7; this agrees with others' observations that the K20's low-light > performance is about a half-stop better. > > When one goes to dxomark.com, things get confusing. Even though the > low-light performance of the K20 is reputed to be about 1 1/2 stops better > than the K10, the low light ISOs are 639 and 522, which is only about a 1/3 > stop difference; and the overall scores (blending low-light ISO, dynamic > range, and color depth) are almost identical. The K7 sensor has a lower > overall score than the K10 by 5 points, having 1 stop less dynamic range and > almost the same low light ISO. > > Which leads me to think that the K10 and K7 sensors' low light performance is > almost the same, and only slightly worse thana the K20's. So where does the > K20's reputedly better performance come from? Firmware? > > Comments or explanations? > > Cheers, > > Rick > > > P.S. I am very intrigued by the dpreview results on the Kx sensor, which (in > RAW) has a chroma noise score of 10 at an ISO of 6400. No dxomark testing > yet. If a similar sensor found its way into a K7-like body, they'd have a > sale. > > > http://photo.net/photos/RickW > > > > > > -- > PDML Pentax-Discuss Mail List > [email protected] > http://pdml.net/mailman/listinfo/pdml_pdml.net > to UNSUBSCRIBE from the PDML, please visit the link directly above and follow > the directions. > -- Boris -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
