Read your camera manual regarding flash exposure compensation. If there's nothing there on that subject, get rid of your current camera and get a real one.

My camera is a Cannon Digital Rebel.  I have played around with various setting including the FE lock.  Sometimes things seem to work and sometimes not.  I am just at a loss as to why it seems so random.  I just never know if it will work properly or not.  Again sometime the histogram is right and sometimes not.

Which mode are you using?

If you are using aperture priority then there can be a tendancy for the camera to under-expose the image (not enough power in the flash for the given aperture).

Programme mode is the simplest and generally gives properly exposed images, though no control and under-exposed backgrounds.

Shutter Priority mode is useful to expose correctly for the ambient light with additional fill in flash, however, if there is insufficient ambient light you will end up with a very narrow depth of field and/or need to use a very very slow shutter speed.

It all depends upon how you have the camera set up, what mode you are using, etc...

Thank you.

I have been experiencing a problem with many photo's taken with a flash either using the built in flash or a mounted flash built for the camera coming out to dark.  I have absolutley no idea why this keeps happening and hope that one of you experts out there can shed some light on this for me.  There are occasions where the picture seems to be a good exposure but it is almost the exception than the rule.  The histogram is always weighted to the left with no data to the right 1/4 of the histogram.  Help please!

Hard to tell.  What camera? What settings? Are you using it like you're suppose to?

Unless you hack the firmware, the Rebel doesn't allow flash power adjustment (flash exposure compensation). This is not very bright on Canon's part, and an error they've rectified with the 350D/Rebel XT. If you choose to hack or upgrade, read this article for tips on how to make E-TTL behave more predictably.

Jonathan,  That article was very helpful and I will certainly try those suggestions

This explains a little bit about some of the issues I raised in the message I just posted regarding my 20D. Do you know if this is an issue with the newer 580 flash? Also, I assume that if you use manual focus it isn't an issue. Why in the *^&%^ doesn't Canon let its users know what is going on!

dr. Gary