Sometime when I am focusing/composing an image I notice that the flash fires off a number of very weak bursts. When I take the photo the flash works fine. Any thoughts?

-- David Pascolla (dpascola@mail.slocs.k12.ca.us), October 06, 1999

Answers

David: Read your owners manual. In E-TTL (Evaluative-Through The Lens) mode, the flash fires off one or more pre-flashes before the mirror flips up and the data is then used to calculate the required flash output once the mirror flips up and the shutter is released.

-- kurt heintzelman (heintzelman.1@osu.edu), October 06, 1999.

also, If you are pressing the AE lock button (*) the 550 will fire a preflash, this is becuase the button becomes a Flash Exposure lock. Other than that the only time is should emit more than 2 is with a stroboscopic flash

Stephen French

-- Stephen French (hello@frenchco,demon.co.uk), October 23, 1999.

If using EOS3 the flash is meant to multiple flash when you press DOF preview to show modelling, particularly good when using multiple 550's Wish I could turn it off when using ETTL for close-ups and really only want to check DOF.

-- Lawrie Weston (westonl@melbpc.org.au), November 17, 1999.

Lawrie,

you can, but it is via a cumbersome custom function CF-6

-- Daniel Taylor (aviator@agalis.net), November 20, 1999.