A hot topic when looking at Pentax from the Canikon camps is the issue of high ISO noise. The Canikons are great in producing nice clean moderate to the higher ISO images fit for web consumption. But the trade off is loss of detail. Pentax chose to not process even the raw file leaving the detail at the cost of more noise in the shots. I find I enjoy using the increased detail AND increased noise as a creative element in the shot. I am not any expert at all so my subjects tend to be, well very simple. I'm still learning to see shots creatively as well as technically but at the same time developing some ideas into how to use the tech differences to my advantage.
Here is an example of a high ISO shot with very basic processing in Lightroom 2.x and no noise reduction (NR) applied. The settings for the shot are above the image.
I converted to greyscale and adjusted the levels only slightly and got a shot I was happy with that has sort of a sense of old film when we learned to use "grain" from pushing film to a speed faster than it was made to shoot. This was just sitting on the headboard of my bed with a single 15w warm CFL bulb as the lighting. It was hand held with the in body stabilization turned on (Pentax calls this Shake Reduction or SR for short).
Pentax K20D, DA 35mm Limited, 1/25, f2.8, IS03200
One of the things that is amazing about the 35ltd lens is not that it's a 35mm focal length true 1:1 macro lens but rather that is this superb close focus lens that works as a nice everyday lens and works out to around a 50mm length lens on a full frame or film body camera (and yes this lens works on FF or film Pentax SLR bodies from 30-40 yrs ago or newer). Plus the bokeh even at 2.8 is wonderful if you plan the subject to background distance with it in mind, or in my case, get lucky because I never even gave it a second though!! hehehe....