How to change the flash output of my camera?

"You changed your F-Stop from f/5 to f/7.1"
Someone said this to me so I looked up what f-stop meant but I don't know how to change it, I'm using a Nikon D200 and when I go in the settings i can't see anything related to flash output. I'm obviously new to cameras sorry if this is simple, thanks.

Did you read your owner's manual, if you have one? If you don't check the Nikon site. There you can download a pdf version.

Most dslr cameras have what's called flash compensation with which you can raise or lower the amount of light put out by the flash but you'll have to have a manual to tell you how.

Basically you will put it in Aperture priority and rotate the command dial watching the LCD on top of the camera. Download a manual from Nikon.
http://support.nikonusa.com/...a_id/13796