What a smooth picture like that!!
These pics above were shot by Sigma DP2s in various ISO settings between 100-400, EXIFs are able to be checked. I must mention that there should be much noise in the picture(especially in ISO 400), but they was erased by the way that I don't know.
These pics looks very "smooth" but with sharp edges, especially compare to the untouched ones like "http://www.flickr.com/photos/pootaro/7533736520/in/set-72157630430289506".
I've tried several ways to perform like that, but none of below was successful.
1. Reduce Noise (or Median) + Sharpen Edges all by photoshop.
2. Imagenomic Portraiture.
3. Use Oil-painting filters.
|IMG_8168ABCD by citori525|
|McKinley meadow by TimR32225|
from Natural meadows
|_DSC2146 by jerste|
from Helios-44 II
|Leopoldsteinersee by RaCor|
from Landscape - Colour #3