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I have a Canon 600ex-rt and Canon 430ex having slave problems


I have a Canon 600ex-rt and Canon 430ex. The 600 is mounted to a new 60D and will be the master, the 430 the slave.  I cannot get a link light on the 600 to light green and of course the 430 does not fire. I have checked groups and channel to make sure they are the same but still will not work.


Is the 430ex capable of being fired in the radio mode from the 600ex-rt?  Is radio control and wireless control the same thing?


Just got the all the new equipment but frustratied that I can't make it work together.


Thanks for any help!




The wireless function of the 430EX is by light not radio. There might be a different setting on the 600 to enable wireless control of the 430EX. But I don't know.


I know the 580EXII works nicely as a master with the 430EXII.


That's correct...


The 600EX-RT is the first radio triggered flash Canon has offered. At present, it will only communicate with other 600EX-RT via radio.


All other Canon flash use the same, long established optical method of communicating with each other. I know for certain the 600EX-RT can do that too, but am not sure how to set it (I don't have one yet). You won't really see the benefits of the radio communication and triggering until you get more RT flashes, to work together with each other.


Unlike radio communication and triggering, optical requires line-of-sight setup. The transparent red panel on the front of both  flashes must be pointed toward each other. Rotate the head on the slave flash around toward your subject, to allow that sensor to face toward the master flash. There's a practical distance limit, too, with the optical communication setup. It sort of depends upon the ambient light.... Outdoors in bright daylight there's less reach than indoors in lower lighting.


The manuals for the flashes should give you guidelines on setting them up and distances.


Alan Myers

San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7D(x2), 50D(x3), some other cameras, various lenses & accessories



On the back of your 600EX-RT there is a small button with a zig-zag arrow (just above the mode button).  That button controls the linking mode of the flash.


As you press the button repeatedly, it cycles from mode to mode.  The mode choices are:


  • Standalone flash (not linked to any other flash) - backlight glows green - no icon in extreme upper right corner of LCD.
  • Radio master mode - backlight glows green - lollipop icon with radio waves around it in upper right corner and the word "Master" will be displayed on the back LCD screen as well.
  • Radio slave mode - backlight glows orange - lollipop icon with radio waves around it in upper right corner and the word "Slave" will be displayed on the bck LCD screen.
  • Optical master mode - backlight glows green - lightning bolt icon appears in upper right corner and the word "Master" will be displayed on the back LCD screen.
  • Optical slave mode - backlight glows orange - lightning bolt icon appears in upper right corner and the word "Slave" will be displayed on the back LCD screen.

You want to keep pressing that button until you get it into Optical Master mode (and to revert back to standalone... just keep pressing the button until the upper right corner has no icon at all and the backlight is green again.)


The link light will ONLY be active in "radio" mode - it is not used in any other mode.


On the 430EX II, you'll have to press-and-hold on the zoom/link (zig-zag arrow) button for a few seconds then use the +/- buttons to toggle it into Slave mode, then press the Set/Sel. button (in the middle of the arrow keys).  


While in "slave" mode, the red panel will flash a red light approx. once per second which lets you know that it is (a) on, (b) in slave mode, and (c) ready to fire again (after it flashes, that light will stop blinking until it recycles and is ready to fire again.)


The sensor which watches for the master is in the lower half of the flash unit.  It must be able to 'see" the master fire.  Remember that the head on your 430 can swivel... so if necessary, turn the base sideway (to face the master) and swivel the flash head as necessary for your shot.



Tim Campbell
5D III, 5D IV, 60Da


Thanks everyone for the help. I apparently misunderstood the options on the 430.  I'm sure they will still work together optically, just need to set it up.



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