When shooting with the flash in a position away from your camera, the camera must communicate various information to the flash, such as shutter timing and shutter speed. The two types of communication are "Optical Communication" and "Radiowave Communication".
Optical Communication uses infrared light in the flash to communicate information when the shutter button is pressed. This method is supported on many different lash units, and is an easy way to start wireless shooting.
However, if there are objects that obstruct the light between the camera and flash, or if you are shooting in clear weather outdoors, the light may not be able to reach the flash, making communication impossible.
The FC-WR Commander and FR-WR Receiver delivers and receives wireless lighting via radiowave control when paired with a compatible Olympus interchangeable lens camera. The FR-WR Receiver also comes with X-RCV (individual settings) for configuring the flash mode and output on the flash connected to the receiver. This design feature makes it easy to operate even during handheld off-camera flash photography.
Radiowave communication is not affected by obstruction or lighting conditions. Also the Olympus radiowave communcation system can reach up to 30m, providing greater freedom over lighting and significantly improved stability.
Check out our brief introduction to the Olympus Flash System in the video below: