Strobe use with Canon A40 - forget it!

Hi all,

I just tried to use a studio flash set up, driven off a flash slave,

with my A40. The idea was to partially cover the A40 flash (using

it just as a trigger), and use the big studio flashes to light the

subject.

Anyway, what I discovered is that this is impossible, becuase the

A40 actually has a delay between commencement of it's flash and the

shutter release. The flash duration on the A40 must be very long,

and the start of the flash fires the studio strobes before the

camera actually takes the picture!

I checked that the flashes weren't late by doing the same test at up

to 1/2 second shutter speed, which would have recorded them if they

were coming in late. Nope, the camera is to blame! So a word to

the wise if you were ever planning to do studio shots with the A40 -

get lamps, not strobes!

And before someone suggests it, of course the red eye reduction was

disengaged ;o)

Cheers,

Antony

I would suspect that the A40 is doing a pre-flash to check exposure, so the studio flash is going off too early. There are special flash slaves available which can be triggered on the second (main) flash instead of the pre-flash.

If you don't see the studio flashes going off, then you have a problem with the slave. But if they are firing, I'm almost certain the slave is triggering on the first pre-flash, before the shutter is open.