I was shooting a stag-do (aka: bachelor party) last weekend and noticed that my assist beam on my 430ii was not firing. I didn't have time to work out what was going on then and there, but am now trying to figure out if my flash is faulty or if there is something I simply don't know about.
I always shoot with my 5Dii in full manual mode, and usually the flash as well. Although in this case I switched the flash to ETTL. So full manual on the body side, AF set to AI Servo, drive set to continuous shooting and I use backbutton focusing, which I've swapped with the * button just to right of the AF-ON button on my 5Dii. This was the setup I was using, and the flash assist beam didn't fire a single time.
So after a little bit of research I figured out that the assist beam will only fire in One Shot mode, not AI Servo. Fair enough, makes sense really. But when I change the above mentioned configuration to One Shot and leave everything else as it is, only the right hand side of the flash assist beam fires, whereas when I switch to Full Auto (green square) both sides of the flash assist beam light up. What gives?? For me the assist beam works a treat especially with the 5Dii AF issues... But I hate not being able to shoot full manual!
Anyone have any ideas what's going on here?