I have a SX20IS. Purchased a Speedlite 430EX. It fires manually, but I cannot get it to flash with any camera setting. Manual says slave and master must be on the same channel. I see how to do this, but what channel do I set it to and is camera the master and the flash attachment the slave?

SOURCE: Slave Flash

I'm guessing you're talking about a wireless connection...

Unfortunately, the 430EX can only act as a slave. You'll need one of the following to act as a master control unit: 550EX, 580EX, 508EX II or the ST-E2 transmitter :-(

Matt

SOURCE: Can the Canon speedlite 430EX be the slave to the 550EX speedlite

Most any slave light will work I use a old vivitar flash with a slave module in the cord to camera outlet woks gook for a fill light. helix camera .com ritz camera. or ebay don't digital flashes a little different than strobes i played with the settings until i got the desired lightng I wanted., if your camera has a hot shoe you can get a slave to fire an external flash with it.hope i helped

SOURCE: Trigger a Speedlite 430EX II with a studio flash

1. Make sure the trigger you are using is compatible with digital flashes.
2. isolate the smaller contact so they do not "short out" on the trigger.
3. make sure the trigger is working and will fire other flashes
   

SOURCE: Only get one flash when using slave

Yeah you should go into the menu on your camera and see if there is anything you need to change!!

SOURCE: aaaaaaaaflash not firing with fresh batteries

Top cover is not communicate with external flash you need to replace top cover and try flash it should work