Could someone please explain this?

joe mama wrote:
"joe mama" wrote in message
...
Two cameras...both with the same film, from the same lot numbers.
developed at the same time in the same tank with the same chemicals. the
difference is, one came out fine, the othe came out as if way
underexposed.

okay, i just happened to find an online manual that says the flash sync i
used wa a p sync, and the other one was the x sync. what would have made
these underexpose?


The X-synch fires the electronic flash while the shutter is wide open,
with a focal plane shutter there are actually two curtains and the flash
fires when BOTH curtains are open. This is why x-synch is limited to
lower shutter speeds. Electronic flash is essentially instantaneous.
Crummy ASCII drawing follows:
XX
XX
_________XX________ time line
shutter open
! flash fires when shutter opens

The other terminal fires the flash BEFORE the shutter is completely open
and is intended for flash bulbs. Flash bulbs "warm up before they reach
peak output. Since you want to use the portion
Another crummy ASCII drawing:
XX
XXXX
_______XXXXXXXX________
shutter open
! flash fires before shutter opens

Mike