look in menu of your camera , in my Canon 20 D , it has a menu with "shoot
w/o card " where you can turn it on or off.

I've just bought a Canon EOS350D/Rebel XT and notice that I can take
pictures (!!!) *without* a CF card in the camera. A message pops up on
the LCD screen on the rear of the camera informing me of this fact,
but I DON'T get any error messages through the viewfinder. This is a
bit of a nuisance as it's then possible to think you're taking
pictures when you're not (that's if you're like me and you don't
always look at the LCD at power-on or during use).

According to the manual the segment of the viewfinder that should
display this this message is also responsible for displaying the
shutter speed, and that's all I see, ie the shutter speed and not the
'no CF' message.

What am I missing? A setup option somewhere to alleviate this?

Fourth menu screen (tools)
Bottom option (Shoot w/o card)
Change to off (Off)

RTFM

RTFM.

Greg

It's not a nuisance - it's designed that way for people who shoot direct to
computer or use the camera via remote control.

Apparently what you are missing is the manual and a good understanding of
why you bought an SLR - you can turn the feature off.  SLR's are not for the
folks who want to point and shoot - they're for people who want very
detailed control over their tools.