Speedlite Transmitter ST-E3-RT
| Manual Flash Output Range | 1/128– 1/1 |
| High Speed Sync | Supported |
| FEB | ±3 stops in 1/3- or 1/2-stop increments |
| FE Lock | Supported |
| FE Memory | - |
| Flash Modes (Exposure Control Modes) | E-TTL II/E-TTL Autoflash, Manual, Stroboscopic, Auto external flash metering |
| Modeling Flash | Supported |
| Flash Exposure Compensation | ±3 stops in 1/3- or 1/2-stop increments |
| Transmitter | Yes |
| Transmission Type | Radio |
| Wireless Transmisson Range (m) (Approx) | 30 |
| Receiver Unit Control | Up to 5 groups & total of 15 units |
| Maximum Flash Count (Approx.) | 10 continuous hours |
| Custom Functions | 8 |
| Personal Functions | 3 |
| Standard Power Supply | 2 size AA/LR6 alkaline or Ni-MH batteries |
| Dimensions (mm) (Approx.) | 67.4 x 61.5 x 77.4 |
| Weight (g) | 110 |