I recently bought a Canon ST-E2 wireless flash transmitter, and have been enjoying the convenience of E-TTL for off-camera flash photography.



The Canon ST-E2 is Canon's dedicated wireless flash transmitter, designed to be mounted on a camera's hot-shoe, and can trigger one or more Canon flashes wirelessly in E-TTL mode.

That's right - the ST-E2 provides remote E-TTL functionality. The ST-E2 communicates with the camera via the hot-shoe, and the ST-E2 communicates with the flashes via infrared to determine the flash power required.



The Canon ST-E2 is a great solution for lazy strobists. With most third-party wireless flash triggers, you need to manually adjust power levels on your off-camera flashes, typically taking multiple test shots to test exposure and light levels, and adjusting the flash output iteratively until you have the right balance.

With the ST-E2 on your camera, you can the camera and the ST-E2 do all the hard work, and control the flashes automatically using wireless E-TTL.

Exposure compensation on the camera can be used to easily adjust ambient exposure, or you can use manual mode to manually set the exposure.
Flash exposure compensation on the camera can be used to adjust the flash exposure, or you can use the ratio functionality of the ST-E2 to adjust flash output relative to the flash output automatically chosen by the camera.

Note that the Canon 7D body has built-in wireless flash capability, and uses its built-in flash to provide similar functionality as the ST-E2.



I'm intending to publish a more detailed review of the ST-E2 in the future, and will also be taking a closer look at the differences in functionality between using an ST-E2 vs using a Canon 580EX as a master device to trigger one or more other Canon flashes.