Part 3: The Functions - The Top

Canon EOS 20D
http://www.all-things-photography.com/images/Top-of-20d.jpg

The top of the camera holds a lot of function and things to know, for instance the light for the LCD display (#1). This is  a button that you can press and the LCD display lights up when needed in low light areas. Second is the AF/White balance button (#2), this button allows you to select what kind of AF you want the camera to do, for instance "One Shot" where when pressed half way on the shutter release button the camera holds it focus on one non moving object or you can set it on "AI Servo" this function lets the camera auto focus on a moving object and makes it stay on focus. Also the white balance lets you adjust the white balance to different light conditions, it gives options like daylight, night time, incandescent light, and fluorescent light.  Next is the ISO button (#3), this allows you to change the amount of noise int he picture ranging from 100-3200, depending what camera. Next is the shutter release button (#4), see post The Functions - The Front. Next is the top dial (#5) allowing you to change settings quickly like the  shutter speed and aperture.
Next the metering button(#6) helps you adjust to different light environments. Next would be the LCD screen (#7) this is where you can view your current settings and view the changes in settings. This has a metering bar, it also shows your shutter speed, aperture, focusing, and how many pictures you can take. Another thing is the hot shoe flash (#8) this place is where you can attach a external flash. Next is the exposure control dial (#9) this lets you change what mode you are in. Last is the pop up flash (#10 see 

The Functions - The Front)