Canon XTI exposure problem?

Flynnstone · Dec 25, 2008

i have the Canon XTI. when i use it in "P" mode i can adjust the av/tv values, but when i pop the flash on to use or add my speelight, the values become locked on whatever the camera decides. but it will take the correct exposure picture.
next, when i set the camera to the AV or TV mode, i can adjust one of the values as i desire, the camera will automatically adjust the other, and the picture is fine. when i add the flash, either built-on or the canon speedlight, the camera will not compensate(automatically), and the picture is over-exposed. i can manually override it, but isn't it suppose to do this itself? or doesn't it work that way in these modes? is this the way all Canon's or even all DSLR's are?

davebmck · Dec 25, 2008

When you are using your flash, you should set your exposure for the background. The flash will expose your subject correctly by adjusting the power level of the flash.

table1349 · Dec 25, 2008

The complete guide to Canon Flash photography.

Flash Photography with Canon EOS Cameras - Part I.

davebmck · Dec 25, 2008

+1 that is an excellent tutorial.

dtornabene1 · Jan 9, 2009

To answer your question, the camera will take over all your setting in an automatic mode. "P" mode as you call it, stands for "Program". This is about the same as turning on automatic. Don't. Once the flash is up or on, you have released all control to the camera so it can find the best exposure. It will not let you change these values.

Start with Av and Tv modes and move up from there. Eventually you will shoot in manual and never look back.

You should have the most control over your camera, not the other way around. Good luck.

-Nick

Craddie · Jan 10, 2009

<<when i add the flash, either built-on or the canon speedlight, the camera will not compensate(automatically), and the picture is over-exposed>>

If your flash shots are coming in overexposed even when in 'P' mode, I can only guess that you don't have it in TTL mode - which gets the camera to meter via pre-flash to expose properly with the strobe.

The other posts are also valid points/suggestions to improve your flash photography (expose for background manually etc.), but if you're simply looking to get your flash shots to be reasonably exposed now, start by ensuring your flash is set to TTL and not Manual.