Canon launched the 600EX Speedlite today, making it the first major update to Canon's official line of Speedlite since the 580EX II was released about 5 years ago. Featuring a GN of 60, CTO gel/filter combinations, the 600EX was a long awaited flagship speedlight from Canon. Partnering with the ST-E3-RT, the 600EX-RT setup will be able to control up to 15 speedlights across 3 groups!
Comparison between Canon 580EX II and 600EX. The Canon 600EX comes in two flavours: the vanilla Canon 600EX and the Canon 600EX-RT.
Both come with an extended range of flash coverage for focal lengths from 20mm to 200mm (most flashes can only cover up to maximum lens focal length of 24mm). They sport an improved dot-matrix backlit LCD display that makes for easier viewing at all angles. The 600EX and 600EX RT also boast a more dust and water resistant design, meant to work effectively with the weather sealing of the 1D X and the weather resistant design of the 5D MkIII.
The Canon 600EX-RT is radio transmission enabled, and is paired with the ST-E3-RT Speedlite transmitter to trigger up to 15 Speedlites slaves in 5 groups. Able to be triggered by radio by the ST-E3-RT, the Canon 600EX-RT does not need a line of sight between the flash unit and the camera.
The ST-E3-RT Speedlite transmitter can be used with the Canon 1D X and the 5D MkIII out of the box, but requires the use of the SR-N3 release cable to be used with Canon EOS cameras that are released before the above cameras.
Currently, the native cameras supporting the Speedlight 600EX-RT and ST-E3-RT are the 5D Mark III and the EOS-1DX. An example of the 7D with the SR-N3 in action, making good use of the radio trigger function. Other cameras suitable includes those from the 1D series (1D Mark III, IV) and also Canon EOS 60D.
Video of Canon 600EX-RT and ST-E3-RT in action
Estimated street price of the Canon 600EX would be ~$750, and Canon 600EX-RT will be $8xx.