>if the flash exposure area is on the subject's
>cheek, and both group A and B reflect off that cheek, wouldn't
>the "base" power be determined by A+B? And the
>actual power of each flash determined by the relative FEC?

No, I don't think so, because right after each group sends its monitor preflash, the commander sends the power of that group right back. It doesn't wait to see if other groups will hit that spot. This indicates that the bases the power of each group solely on the amount of reflected energy from the monitor preflash for that group.


>I think I made that clear as mud. Basically, I think I'm
>asking "Won't CLS compensate for overlap if the overlap
>is in the flash exposure area?"
>
>Ok, I just thought of a simple experiment. Two lights in two
>groups hitting the same target with the same power. If it
>overexposes the target then I'm wrong. If the exposure is
>correct then I'm right. Right?

I have tried this, and I see no indication of a change in power based on whether the flashes overlap. As far as I can tell, they simply add, which I'm guessing is why they set each group to underexpose by a stop or so.

Russ
Russell MacDonald Photography
Nikon CLS Practical Guide