Im sure some of you have already heard and seen the Canon iso test. But I thought I would do my own test of my Canon T3i. If you were not aware of the native iso that these cameras have this is the run down.
Native iso are multiples of 160. These give the cleanest less noisy images in video mode.
Even though iso 100 in theory should have less noise then 160 it does not, as you can see in this test.
What I did was put on the lens cap and filmed a few seconds of each iso setting. I had the picture profile set to neutral and 1/50s at f/4. Then in after effects I added the levels affect to each clip to increase the brightness of the clip so the noise stands out better. The levels setting were exactly the same for each clip.
As you can see the native iso listed above will give you cleaner video.
And if you are using the Magic Lantern hack these native iso are highlighted in green in the menu so it makes it easier to remember. Just use the green highlighted iso in Magic Lantern unless you have no choice but to use another iso.