Optimum ISO levels for noise

I was just watching a video by Shane Hurlbut where he mentions that ISO 160, 320, 640, 1250, and 1600 gives the lowest noise. Why is this the case, and is this applicable to both still and video shots? Thanks for any inputs!

I think the theory is that it is the next higher ISO which is pulled down, rather than pushed which increases noise.

artyman wrote in post #13053874
I think the theory is that it is the next higher ISO which is pulled down, rather than pushed which increases noise.

Could you elaborate a little on what you mean by pull/push?

mrmarks wrote in post #13053963
Could you elaborate a little on what you mean by pull/push?

He means over and under exposing slightly... If your image is dark and you brighten it using post processing, you bring out the noise a lot more than if you overexpose it slightly and darken it using post processing..

It's been suggested that using whole ISO stops (100-200-400-800 etc) provide less noise because they are native stops and the stops in between involve over or underexposing.