From Night Photography blog by Andy Frazer: More 5D Long Exposure Tests:

Seattle-based night photographer Brian Chapman has posted another set of 5D MkII long exposure tests, this time all taken at night. Although this set was taken at ISO 400, underexposed, and then pushed during RAW conversion, the results are very interesting.

Brian Chapman’s experiments are essentially a night photographer’s torture test – shooting at high ISO, underexposing, compensating in post, adjusting the image, and including areas of uniform color and luminosity. If you aren’t familiar with real life noise issues in digital photography you might think, “Ugh! Noise.” If you have done night photography and made prints for images like those in the test you might be thinking, “Hey, that’s pretty darn impressive!”