Just see this self-explanatory post:-
http://forums.dpreview.com/forums/read.asp?forum=1019&message=32904182
Well, I do agree with most of the poster observed and said. I think he is right.
But, I think if both low noise and high image details are desired at the same time, Full Frame is the only way to go, still. APS-C is just a dead end and I think the pixel count limit just lies somewhere in between 10 to 12 MPs, but should not be more, for the current technology limit.
Having said that K-7 does produce images that have more details retained at higher ISOes, it doesn't mean that its JPEGs are not soft when you view in full, see my previous shootout here.
And, I think with more pixels packed in a small APS-C sensor of the Canon 7D, its image quality would possibly be even inferior than its predecessors, especially when higher ISO speeds are used. Just see another previous shootout on the noise and details test comparison amongst the K-7, K20D and 50D and you can see the differences.
Btw, for that image details and textural feel of my own DSLR bodies, namely, the Canon 5D and K-m, I do like more about the K-m in giving me overall more skin texture instead of somehow plastic skin of the Canon but together with some little noise (which I have found some best settings to minimise/suppress them anyway). However, when I view the picture in full, doing cropping or just pixel peep, the 5D images are actually having better per-pixel sharpness and much better per-pixel smoothess also, i.e., far less pixelisation when viewed 100%. In fact, the K-m images are suffered from more pixelisation as it can be easily seen, regardless of the different values of the Sharpness setting. Just see my this previous pixel-peeping shootout between my K-m and 5D and you will know what I am talking about - there is no way to eliminate those as long as the in-camera JPEG engine is used, i.e., unless the user shoots RAW and uses other software converters to produce the final images.
Last but not least, I just wish to tell that my K-m quick review (not a measurbating one) and "tips and tricks" article has been delayed than what I original intended to publish as told last time (in July) as I have been just so busy and too busy during the period (and still so up till now). I would like to apologise to those who are actually waiting for my that article and I hope I can publish it by mid-September and I will try my best to do it this time (as it has been delayed for long now).
In my that coming K-m article, I shall tell about how to extract most image details, whilst having minimal noise plus more dynamic range with the K-m - getting the best of three worlds, but not just both! Just believe it or not! You can really achieve that with the K-m! Well, the good thing for my delayed published article is that I have actually used my best (single set of) settings to shoot a wide range of objects and different types of photography to verify its effectiveness (and accuracy as well). Stay tuned, I think my own research and information to be provided and shared will be useful and beneficial to all K-m users and maybe also to other Pentax DSLR users with a different latest Pentax model as well, as some principles do apply, I believe. In short, I just think that the default settings as chosen by Pentax in each of their newer models are just not so good and unwise, enough said - they provided the options but they did not actually select the best ones and the best combinations as the factory defaults! :-(