The Canon EOS Rebel G  is the low-cost member of the Canon EOS line.  Still, it has many features in common with top-line cameras, and it offers full manual control.  It's small size, light weight, and low cost make it the ideal camera to use as a back-up, to backpack in to a remote location, or to carry into a situation where you don't want to risk a more expensive camera.  The Rebel G has been replaced by the Rebel 2000, which is very similar.

To change the lens, place the camera strap around your neck.  Hold the camera facing away from you in your left hand, and use your index finger to press the lens release button (blue arrow, right).  With your right hand, rotate the lens to the right (counterclockwise) so that the red dot on the lens moves up to the 12 o'clock position, where the lens will release.  Cap the rear of the lens you have just removed with the cap from the lens you are mounting.  Place the new lens with its red dot at the 12 o'clock position (there is another red dot on the lens mount to guide you) and twist it to the left about 30 degrees until it locks into place.  Be sure the lens is firmly mounted before letting go.  Be sure the lens that you removed is secured in your camera bag (and the bag is closed) before proceeding.

If you are not in an automatic mode, you will need to take additional steps before pressing the shutter button completely:

1. If autofocus is not on, you will need to focus manually by turning the focusing knob on the lens until the subject is focused in the viewfinder.
2. If you are in Tv or Av mode you will need to select the shutter speed (or aperture) by turning the main dial (red arrow, above) right or left to select the appropriate value.  The camera will match your selection, if possible.  A blinking number in the viewfinder means the camera cannot match your selection and you will need to make an adjustment.
3. If you are in Manual Mode:

   	Turn the main dial (red arrow) to select the shutter speed.
   	Press and hold the aperture button on the back of the camera (purple arrow, above) and left) with your thumb while turning the  main dial to set the aperture.
   	For "correct" exposure, make sure the exposure meter in the viewfinder (or in the LCD panel on top of the camera [red box, above]) is centered.

4. When focus and exposure are set, take the picture.

3. Exposure compensation: You must be in the P, Tv or Av mode!  Press the exposure compensation button (which is also the Av button - purple arrow above, right) and turn the main dial.  You can adjust the exposure in 1/2 stop increments up to +/- 2 stops.  The change is reflected in the exposure meter on the LCD panel (red box) and in the viewfinder.  To the left is underexposure, to the right is overexposure.  Exposure compensation is canceled in the manual mode and in all the icon modes.
4. Partial Metering/AE lock: Normally the camera uses evaluative metering, which may fail if the background is particularly light or dark.  Partial metering limits the exposure reading to the central circular area defined in the viewfinder. You can make a partial metering exposure by:

   	Focusing on the subject.
   	Pressing and holding the AE lock button on the back of the camera (green arrow, above).
   	Recomposing the picture (if you don't want the subject at the center.
   	Pressing the shutter button all the way down to take the picture.

5. Autoexposure Bracketing:  You must be in the P, Tv or Av mode! Press the function button (green circle, above) until the arrow at the right of the LCD panel points to the bottom of the four icons at the right of the screen. Rotate the main dial to the right.  The exposure meter (red box) will gain two additional squares, with the new squares appearing to the right and left of the one in the center. Rotating the main dial additional clicks will spread the squares out.  You can bracket 1/2, 1, 1.5 and 2 stops; the amount of bracketing is displayed in the LCD panel.  Next take three pictures of the subject.  The first will be normally exposed, the second will be underexposed, and the third will be overexposed by the amount you dialed in.  To cancel this feature, follow the directions above, but turn the main dial to the left until the squares merge and the exposure bracketing reads 0.0.
6. Red-eye reduction: To reduce red-eye when using flash, choose this function.  Before the flash fires, a bright light on the camera will shine into the subject's eyes, momentarily blind them so that you can take their money.  Actually, it closes down the irises of the subject's eyes, thus reducing red-eye, but it is pretty damn annoying.  To turn this feature on, press the function button (green circle, above) until the arrow at the right of the LCD panel points to the top of the four icons at the right of the screen. Rotate the main dial to the right to turn it on (1) or left to turn it off (0).  If the feature is on, a triangle will appear opposite the icon.
7. Beeper: You can turn the beeper that sounds when focus is achieved on or off.  Press the function button (green circle, above) until the arrow at the right of the LCD panel points to the second of the four icons at the right of the screen. Rotate the main dial to the right to turn it on (1) or left to turn it off (0).  If the feature is on, a triangle will appear opposite the icon.
8. Multiple Exposures:  You can set the number of exposures that will be made before the film is advanced.  Press the function button (green circle, above) until the arrow at the right of the LCD panel points to the third of the four icons at the right of the screen. Rotate the main dial to the right to increase or left to decrease the number of exposures from 1 to 9.  If the feature is on, a triangle will appear opposite the icon, and the number of exposures to be taken on a single frame will be displayed numerically. Note that you will need to adjust the exposure or the resulting images will be too bright.  As a general rule, use the exposure compensation and decrease it by 1 stop for 2 exposures, 1.5 stops for 3 exposures, and 2 stops for 4 exposures.  Of course, you will have to experiment.
9. Flash: In the icon modes, the built-in flash will pop up automatically if needed.  In the P, Tv or Av modes, press the flash button (red arrow, right) to activate the flash.  In these modes, the flash will try to supplement natural light.  A blinking number in the viewfinder indicates that the background may be overexposed or underexposed.  While the subject will probably be normally exposed under these circumstances, you may want to adjust the exposure settings until the blinking stops.  

   	You cannot set a shutter speed faster than 1/90 of a second with the built-in flash.
   	You cannot use the built in flash with any unit attached to the hot shoe of the camera.
   	The subject must be at least 1 meter (3 feet) away.
   	With 100 speed film, the range of the flash is up to 12 feet (4 meters) with a wide angle lens, and 6 feet (2 meters) with an 80mm lens.
   	Be sure the lightning symbol appears in the viewfinder to the left of the shutter speed.  This indicates the flash is charged and ready.  You may have to wait between shots for the flash to recharge.
   	Use of the flash will drastically reduce battery life.
   	To use a Canon flash, simply mount it in the shoe.
   	Do not use non Canon EOS flash units.  Although they may "fit" the electronics may not be compatible and you will damage the camera and the flash.