The Canon Speedlite Transmitter ST-E2 and the PocketWizard FlextTT5-Canon Transceiver work with external off-camera flash units. The ST-E2 operates as an infrared flash controller for Canon Speedlites. The PocketWizard operates as a radio trigger to trigger flashguns and studio lights. Both wireless technologies reduce the need for long and possibly hazardous cables between the camera and flash units.
Exterior
The Canon ST-E2 mounts on the body of the EOS hot shoe and secures with a shoe lock lever and locking pin. The FlexTT5 mounts on the EOS hot shoe and also connects the Canon Speedlite for a combination of remote and on-camera flash. The Flex transceiver also attaches to a command unit. The ST-E2 transmitter does not support an external flash unit on top. The compact ST-E2 measures 2.4 inches wide by 2 inches high by 3 inches deep. The slightly larger FlexTT5 measures 2.9 inches wide by 1.4 inches tall by 3.6 inches deep with the antenna down. The lightweight ST-E2 weighs 3.5 ounces without the 2CR2 lithium 6V battery. The FlexTT5 weighs 5.4 ounces without the two AA alkaline batteries.
Channels
The Canon ST-E2 provides four channels. The ST-E2 works as a master flash unit with up to three Canon 550EX Speedlites set as slave units with different flash ratios, if preferred. The ST-E2 emits the infrared signal to trigger the flashguns in its line-of-sight. The FlexTT5 radio, in contrast, has two channel configuration settings with programming up to 52 channels over 26 frequencies (FCC/IC) and 35 channels over 5 frequencies (CE). The radio frequencies are 340.00 to 354.00 MHz US FCC/ICC and 433.43 to 434.42 MHz CE. The TT5 can work with the PocketWizard Mini TT1 Transmitter or another Flex TT5 Transceiver for a much wider flash system than the ST-E2.
Range
The Canon ST-E2 has an effective range of 39 to 49 feet indoors and 26 to 32 feet outdoors. By contrast, the FlexTT5 features a more extensive range from 30 to 800 feet for evaluative through-the-lens metering, and 30 to 1200 feet for basic triggering, with variations according to flash unit, antenna orientation and other factors.
Synchronization
Both the ST-E2 and the Flex TT5 operate with high-speed focal plane flash synchronization speeds up to 1/8,000 second, depending on the camera model. For example, the Canon camera body EOS-3. Both devices work with any camera f/stop or shutter speed. For example, setting a larger aperture can produce a more shallow depth-of-field for a pleasing background blur behind a sharply focused subject.
Tags: Canon ST-E2, flash unit, work with, Canon Speedlite, channels over, channels over frequencies