The RT Speedlite Transmitter is a wireless transmitter that can control multiple 600EX-RT flashes simultaneously. This allows a photographer to move up to 98 ft away from a flash and still control it. Those of you who are new to wireless flashes, will enjoy an easy to setup menu, an intuitive control system, and an increased flexibility. Veteran users will notice some pretty unique features out of the ST-E3-RT. Most notable advantages are the ability to control up to 5 groups, or 15 different individual flashes, and the new radio controlled system doesn’t get blocked by physical obstacles! This opens the door to many new possibilities.

I decided to test the transmitter along with Canon’s 100mm Macro lens and 180mm macro lens. The freedom of being able to control multiple flash sources and their outputs from 10ft away opened up the options for photography. I have tried to shoot food in my apartment before, but found it just too dark. With the transmitter though, I didn’t need to run any wires, setup any heavy lights. I just set a flash on a stand and moved freely to make my shot.

During my shoot I found that the flash I had closest to the sushi was firing too hot. Instead of walking the 10ft over to the flash and adjusting settings, I could control them without moving. So without changing my shot, changing my focus, or even moving my camera I knocked its output down a stop and got my shot. In the time it would have taken me to go over, adjust, test shoot and go back, I had already started shooting again and moved onto the next shot.

Personally I found this liberating. I was trying out a new lens, 180mm macro, and I was able to focus on my framing and look because the ST-E3-RT and 600EX-RT are both so intuitive. I had never used the transmitter but after only 10 min I was up and shooting with it, and after 10 min more I had a full grasp on how to use it. I can’t really say that about any other flash transmitters.

If you are a photographer who will be on the move but want a consistent flash, then Canon’s ST-E3-RT Speedlite Transmitter will be a welcome addition to your kit!

-Michael Grady