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Canon Speedlite ST-E3-RT
8.8 out of 10

Canon Speedlite ST-E3-RT

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Radio transmissions wireless Speedlite transmitter
Compatible Cameras
Type A EOS cameras (E-TTL II/E-TTL autoflash)
Sync Speed
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
Wireless Functions
Transmission System
Radio Transmission
Transmission Range
Approx. 98.4 ft. (30m)
Flash Ratio Control
1:8 - 1:1 - 8:1, power 1/2-stop increments
Flash Coverage
Transmission Angle: 360° all around
Slave Operation Confirmation
Green Light Lit: Radio Transmissions Okay Red Light Lit: Not Connected Blinking: Transmission Error/ Too many units (Master units + slave units = more than 16 units) Orange Light 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.
Power Source
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).
SE Mode
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
3.9 oz. / 110g (excluding battery)
Release Date
First seen
4 March 2012