I stumbled on a discussion surrounding the Canon DSLR cameras that showed that the best ISO settings for APS-C sensor Canon DSLR in video mode were the multiples of 160 (160, 320, 640, 1250, 1600). Here is a link to the video that Andrew Schär put together on Vimeo: http://vimeo.com/23082874. Andrew indicated that it’s a side effect of the CineStyle profile on the 60D and the way it handles dynamic range. I’m not sure if the 60D does the same thing natively. In any case, this should at least keep Nikon shooters from running around at ISO 160 for no apparent reason…
Shutter speed: 1/50s
I followed a similar method to Andrew. I recorded clips with the lens cap on, imported them in to Adobe Premiere Pro CS4 and arranged the clips. I then grouped the clips so that I could apply the same curves, brightness, and contrast across all the different videos. The contrast boost is really high to accentuate the grain, so it wouldn’t look this bad if you were shooting real video.
The test seems to show that the Nikon D7000 doesn’t have the same 160-multiple sweet spots. The grain seems to get progressively worse as the ISO is increased, so shooting at the lowest ISO you can in a situation is recommended.
Here is the video. I recommend watching it in full-screen mode to get the best effect.
Below is a compilation of the different ISO side-by-side.