Setting up 470ex-ai and 430exIII-RT speedlites as master/slave

[probertson]

I'm trying to set up two flashes as master/slave. My master is a 430exIII-RT and my slave is a 470ex-ai, which can be used as an wireless optical unit. Can't seem to get them to connect. They're on the same channel and both on ETTL. The 430 is connected to my 6d with a flash cord. The reason for this is I'm trying to set them on a table to get light underneath a setup for macro. It initially worked, then when I changed the power, the connection light went red. 
Can't get the green light back. Any suggestions?

[Waddizzle]

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@probertson wrote:

I'm trying to set up two flashes as master/slave. My master is a 430exIII-RT and my slave is a 470ex-ai, which can be used as an wireless optical unit. Can't seem to get them to connect. They're on the same channel and both on ETTL. The 430 is connected to my 6d with a flash cord. The reason for this is I'm trying to set them on a table to get light underneath a setup for macro. It initially worked, then when I changed the power, the connection light went red. 
Can't get the green light back. Any suggestions?

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What do you mean by “changed the power”?

I have not tried your configuration, but I have noticed that the order you power up stuff can make a difference.  My 6D may not recognize my 600EX sometimes.  I must first power up the flash, and then camera, which always works.

[probertson]

I mean reduce the flash output.  I'll try changing up the power up order and see if that works.  Thanks

[kvbarkley]

Can you use the 430exIII-RT as an optical master?

[probertson · Accepted solution]

I was trying to set up the 430 as an optical master or sender but Canon support has now informed me that I would need an infrared transmitter to be able to control the 470.  The only thing I could use would be the ST-E2, the old version, not the new RT version.  The 470 does not have RT capability.

Thanks