Most of the time, my RF-603 will be used in the simple manner shown above: transceiver in the hotshoe of my 7D and wirelessly triggering a remote flash or two. However, the RF-603 can be used as a shutter trigger or even combined shutter and flash trigger.
In the previous post, I noted that the button on the RF-603 transceiver activates only the shutter release (side connection using 2.5mm plug) and not the hotshoe functions. As shown above, the RF-603 can be used as a simple wired shutter release. Press the shutter button and the camera fires but remote flashes will not be triggered.
The configuration shown above will trigger both camera and remote flashes. Place a transceiver in the hotshoe of the camera and connect its shutter release to the camera. Add a second transceiver to trigger the hotshoe transceiver. Now a press of the button on the second transceiver triggers the shutter release on the first transceiver (the one mounted on the camera hotshoe) and the camera fires. When the camera fires, the hotshoe mounted transceiver transmits a signal to any RF-603 that are listening and those flashes will fire. To operate in this mode, three transmitters are needed: one on the camera hotshoe, a second transmitter to be the shutter trigger and a third transmitter mounted on the flash.
Actually, the “third” transmitter (the one mounted on the flash as shown above) can be used to trigger the transmitter mounted on the camera hotshoe so really only two transmitters are needed. In other words, set up a RF-603 on the camera hotshoe and wired to the camera release connection plus a second RF-603 mounted on the flash hotshoe as shown below. When the button on the flash mounted RF-603 is pressed, the camera will fire and activate the RF-603 on the camera hotshoe which will trigger the flash mounted RF-603 to fire the flash having the transceiver that began the cycle.
All this is simpler than the words necessary to describe it. Just remember that the button activates the 2.5mm connection and the hotshoe activates remote hotshoes.