Quote Originally Posted by neuroanatomist View Post
E-TTL does use subject distance, but much of the exposure calculation is based on the pre-flash.

I just shot a family gathering in a room with a pair of 430EX II's on Justin clamps, bounced off the ceilings, triggered with PocketWizards (Mini TT1 and 2x Flex TT5s) using E-TTL. Exposures were perfect.
Yep, What Neuro Said---I don't understand all of the electronics, but ETTL just seems to work---Regardless of Distance to subject. I commonly use ETTL for fill flash when shooting birds or other wildlife, I just reduce the the exposure by 2 1/3 stops---gives me perfect fill without over exposing the subject in relation to the background---

Also, I am not familiar with other triggers, but the pocket wizards specifically state to conduct a test shot first, which tells me that it is actually measuring the light, not simply calculating distances, flashpower etc.