You can disable the sender unit from firing so that only the receiver unit( s ) will fire a flash. Press the button so that the display blinks as shown on the left Disable the sender unit's flash firing
CFn-05-1 is geared for EOS -series film cameras .Do not set it if you have a. EOS DIGITAL camera or the E0 S REBEL T2 / 300 _ If CFn-5-1 is set for such cameras, the flash control will not work properly The flash might not fire of it might fire only at full output With Type-A cameras, if C.Fn-05-1 is set, wireless autoflash shooting will not be possible,
The flash head can be extended or retracted manually to match the lens focal length. As the focal length of EF lenses and EF- S lenses differs, extend or retract the flash head while referring to the table below (the flash head position in relationship to the lens focal length).
Flash exposure compensation and other setting set with the sender unit will also be automatically set in the receiver units. Thus, you need not operate the receiver unit( s ). Wireless flash with the following setting can be done in the same way as with normal flash shooting
To prevent your sender unit from firing another photographer's receiver units, four channels are provided to differentiate your receiver units from unrelated ones. The sender unit and receiver unit( s ) in the same wireless flash system must be set to the same channel No.
Sample Wireless Flash System You can easily set up an E-TTL autoflash system with the 550EX, ST-E2 or MR-14EX as the sender unit and the 420EX as the receiver unit. Just set the 420EX's wireless selector to <receiver> and position the receiver unit( s ) as desired within the wireless transmission range