Can someone please help me check whether pre-flash fires under these conditions:

- EX series flash on manual settings
- 300/350/400D body on manual exposure settings

Thanks.

hello wkkay,

yo query seems to b not identical enough.

if i m not misunderstood of yo queries .

this is wat i would comment:-

pre-flash is in fact used to ( by d camera system ) calculate d accurate exposure for a certain shot, where aperture , shutter speed , ambient lighting , subject's distance from flash are taken into d calculation, just b4 d shot is taken , and it functions in any other mode other than "manual" ( set in flash itself , manual mode in camera body is another story )

.

I'm asking because I plan to buy some cheap slave flash triggers. The ones I'm looking at don't work when there's pre-flash.

I want to make sure that an EX flash doesn't pre-flash under manual settings. Conventional wisdom says that it shouldn't.. but I prefer to see what happens in practice.

IIRC i've read it somewhere, for 580EX , you can cancel the 580EX from firing a preflash when you want to trigger other flashes.

If you wnt a cheap alternative to flash triggers, you can try out this
coz it's as good as what other strobists says

Conventional wisdom says an external flash on manual power mode should not pre-flash.

To test, change to Shutter Priority, set second-curtain flash, and set the shutter speed to 1 second or longer. You should see only one flash. I don't have a Canon so I cannot verify the theory.

If you can set the flash power on the body (1/32, 1/4 etc.) then it should be possible; if you can only control flash exposure compensation then it will still need a pre-flash to refer to.

Conversely, you could do a cheap hack; using Manual Exposure mode, 1 second, F22, you could cover the built-in flash with your hand when it pre-flashes and then remove it after. However, because you covered the pre-flash it will fire at full power, so you need to compensate by choosing a very dark aperture and low ISO. This should effectively trigger the optical slave.

eh, wkkay got a digital slr ard?

Nopes.. still on film for my personal stuff It's when I shoot friends' graduations, birthdays etc I borrow a DSLR.