Not too much of a tangent...100
But, what about the 80, 160, 320 and so forth ISO settings that are supposed to be better than shooting 100, 200, 400 etc with the 7D? Is there any truth to this?
/200/400/800/1600/3200/6400 - These are native ISO values achieved by hardware.125
/250/500/1000/2000/4000 - These are ISO values achieved by applying 1/3 EV gain to the closest, lower full ISO value which results in more noise and lowered dynamic range by 1/3 EV.160
/320/640/1250/2500/5000 - These are ISO values achieved by applying negative 1/3 EV gain to the closest, higher full ISO value which results in less noise and lowered dynamic range by 1/3 EV.
Long story short:
Photography in RAW - doesn't matter.
Photography in JPEG - avoid "base + 1/3".
Video filming - stick to "base - 1/3".
Own experience + link
EDIT: more links - link