"Mirror up" causes flash to trigger

I remember reading about this elsewhere on these forums, but can't find it.

Is there a way to stop the flash from triggering when using a remote with "mirror up" enabled on the mirror up cycle?

I can live with it, but it's annoying.

20D body, TC-80N3 remote and EF-500 Super strobes.

Thanks.

That's the E-TTL preflash. It has to fire before the mirror goes up.

Using manual flash will get rid of it.

Mirror lockup and flash aren't often used together. I'm curious what you're trying to accomplish.

Curtis N wrote in post #2015407
That's the E-TTL preflash. It has to fire before the mirror goes up.

My idiot light goes off again. Thanks.

Just trying to inch out every bit of sharpness I can. Doing some macro work and using some lower shutter speeds to affect the background. The shutter speeds, IMO, are in the range where MLU would be beneficial.