jphalter@ihuxb.UUCP (J. Halter) (02/03/84)
Since I just bought a flash for my Canon AE-1, I think I can answer this
question. There are three types of flash units available (as far as I know):
Manual: You set the distance on the flash, the aperture on the camera,
and the shutter speed on the camera, the flash intensity is
constant
Automatic: You set the distance on the flash, the aperture on the camera,
and the shutter speed on the camera, but the flash intensity
varies depending on the amount of light measured from the subject
during the exposure
Dedicated: Same as automatic, but flash unit forces shutter speed to
1/60th sec. on a Canon.
I decided to buy an automatic Sunpak and opted against buying the dedication
module for Canon's (~$50). I figured for $50, I could set the shutter speed
to 1/60th. The automatic (thyristor) flash is worth every penny. The manual
flashes that I previously used did not produce consistently exposed pictures
(Mostly because the distance between subject and camera varies)