Radio transmissions wireless Speedlite transmitter
Type A EOS cameras (E-TTL II/E-TTL autoflash)
High-Speed Sync provided (EOS-1D X and EOS 5D Mark III only)
Flash Exposure Confirmation
Flash exposure confirmation lamp lights in green
* If it does not light, shooting is not performed with the standard exposure
AF Assist Beam
Approx. 98.4 ft. (30m)
Flash Ratio Control
1:8 - 1:1 - 8:1, power 1/2-stop increments
Transmission Angle: 360° all around
Slave Operation Confirmation
Lit: Radio Transmissions Okay
Lit: Not Connected
Blinking: Transmission Error/ Too many units (Master units + slave units = more than 16 units)
Lit: Sub-master transmission
Blinking: Receiving remote release shooting, linked shooting signal
Slave Unit SE Mode Cancellation
The test flash button can be pressed to test if the slave units fire or cancel the auto power off status.
AA/LRG Alkaline Batteries x2
(Ni-MH and Lithium batteries can also be used)
Battery Life: Approx. 10 hours continuously
*When using AA/LR6 alkaline batteries used (At a room temperature +23°C/73°F).
Power off after 5 min. of idle operation
2.65 (W) x 2.42 (H) x 3.05 (D) in. / 67.4 (W) x 61.5 (H) x 77.4 (D) mm
Great radio, when there's ambient light
I used the ST-E3-RT with 3 600EX-RT flashes for a wedding reception and loved the ease of the system and the results -- that is, when I could focus.
There is no focus assist beam when the radio trigger is on-camera, so as soon as it gets dark, focus performance diminishes significantly. You then have to mount one of the flashes on-camera to get improved focus, which defeats the whole purpose of off camera flash.
So, the radio system works best when you're trying to create some fill in good-to-average light situations. Once it gets dark and you want to use the system to create off camera light, you're out of luck.
April 28, 2014
90 % perfect
This is a product I have wanted for a long time, and it works very well, but......
It should articulate like the flashes do, meaning go from the flat position that is currently to a screen up, vertical position so it can be read when the camera is at an eye level position on a tripod. I would like to see this change made in a new product. Very frustrating to have to either remove it from camera or remove whole camera from tripod to change settings, or carry a small ladder to be able to see the screen while it is mounted to a tripod. Just my 2 cents. I own a lot of canon gear including four (4) 600 ex rt speedlights which I love. Make this product go from good to GREAT! You can do it.....
February 23, 2014
Where's the AF assist beam?
Everything works great except No AF Assist Beam. Need that beam, put that in asap. The main flash 600EX-RT must be mounted on the camera at all time at night time, so what's the point of buying this ST-E3-RT then?
December 14, 2013
Also have a single 600 flash. Wish they had an adaptor for my 580 flash. But great for getting rid of the cord for macro, hand pointing the flash, remote location of flash. I will be adding at least 1 more 600 flash to the arsenal.
October 11, 2012