I recently picked up a pair of the new PocketWizard units that do E-TTL with a Canon speedlight. Essentially, you put one of these on your camera's hotshoe and one on the the flash and then the flash and the camera act as if they were directly attached. You can move the flash wherever you want and the auto-metering "just works" and the exposure is supposedly all taken care of. You can even dial the flash compensation up and down on the camera and the flash does the right thing. That's the idea, at least.
So, I went back to Florida for another party and experimented with putting a gelled softbox (about 10 inches wide) over the flash and holding it a few feet away to try to add a little color to the scene. If you had seen any photos from the last photoshoot you would remember that the venue is pretty plain looking. Adding a little color to each shot from the side really adds a some punch, and what says "party" more than colored lights? Who cares if there are colored lights in the cafeteria line?
The way E-TTL works is there's a pre-flash that fires right before the shutter trips and the camera uses this pre-flash to figure out how much power to use for real when the picture is actually being taken.It turns out the the exposure meter is not equally sensitive to all colors of light, so with some colors the flash would be way too string and other colors the flash would be too weak. For really mild colors it was pretty much dead on though.
The system clearly works although there are some quirks. First of all is the range. It's well known by the company that some flashes emit huge amounts of RF interference which really cuts the range. I found that I could get 20 feet pretty reliably but that was about it. There are PocketWizard-supplied RF shields you can put around your flash to block out the badness, but that seems really awkward. (I've got one on order, so I'll let you know how it turns out.)
In conclusion, it was a great experiment. I look forward to using the system for more conventional, non-party uses in the future. If there were some sort of technology that allowed me to share pictures with you on this blog, I'd show you just how exciting the party looked, but alas, that technology hasn't been invented yet.
Until next time...