Speedlite 430EX and canon 7D wireless

[Osx]

I try my speedlite 430EX wirelessly using my Canon 7D to go off through the flash menu. Now that all works but when I make a picture in the mirror I see the internal flash on the picture. Is it not true that the internal flash to go off a little earlier.

[p4pictures]

I have seen similar myself with other master flashes set not to fire as part of the exposure.

My take is that as the master flash (pop-up on your 7D) needs to send the pulses of light to the slave flashes then it is still emitting a low level of light due to the tail-off effect. It had to send the "fire now all you slaves" command right before the shutter opened, or even as the shutter opened. Hence it shows up in a mirror, but actually it's usually of such a low level that it won't impact the picture.

Brian

[7D5D]

If  I'm understanding your question correctly...

This might be stating the obvious but double check to make sure your built-in flash is set only for triggering a remote flash and not for built-in flash + external flash.

Flash Control menu

Built-in flash func. setting

Wireless func.

- middle icon (Speedlite only)

Now your camera will fire a pre-flash to trigger your exterior Speedlite without the pre-flash as part of your exposure