The Canon EOS Digital Rebel XS/1000D Companion

Using the XS's On-Camera Flash

In Chapter 7, you saw how you can use the on-camera flash to even out an exposure by brightening a dark subject when your background is too bright. You've also seen how you can use fill flash to even out darker shadows in a scene.

But there will be times when you're in a dimly lit room and simply need some extra light. In these snapshot-type situations, the XS's onboard flash can do a good job of illuminating your scene, but you might need to take a little more control to get a good shot.

Flash Exposure

When you half-press the shutter button while the flash is popped up, the XS calculates an exposure, just as it does when the flash is down. However, with the flash up, it bases its exposure on its understanding of how much light the flash will be able to add to the scene. The camera will never pick a shutter speed slower than 60 to ensure handheld shooting. It will also never pick a shutter speed faster than 200, because it's not possible for the entire sensor to be exposed to the flash if the shutter speed exceeds 200.

When you take a shot after metering, the camera will turn the flash on. When it sees that enough light has been added to the scene to properly expose it at the current settings, it then turns the flash off. In other words, while it might appear that the flash is always just a quick flash of light, the XS is actually carefully monitoring the situation and firing the flash for longer or shorter periods of time.

Waiting for Recharge

Before the ...