I want to take night shots, with no flash, and want to use the 2 second delay rather than 10 second. So how do I use mirror lockup without firing the flash?
Steve is right. On Tv, Av, or M the flash will only fire when you hit the button on the left of the flash on the 400D no matter how dark it is. On Auto (the green square) the flash will pop if it’s too dark but you can’t make it pop up yourself as the retains complete control of it in Auto (on Canons and Nikons anyway).
An interesting quirk of the 400D is that the self timer is locked at 10 seconds, you can’t change shorten or lengthen it. But when you set mirror lock-up (Custom Function 7) the self timer sets to about 2 seconds. Strange but cool,