I put together a few quick frames from ISO 1600 to ISO 25600 for the Nikon D700 and Canon 5D Mark II tonight. Nothing scientific, just a few shots snapped off at my desk. Settings: tripod, aperture priority @ f/8, evaluative metering, auto white balance, ISO 1600-25600 in full stops – lenses used were 50mm f/1.8 on the Nikon & 50mm f/1.4 on the Canon – RAW capture – exported to JPEG via Lightroom