The Canon EOS Digital Rebel XSi/450D Companion

CHAPTER 2

CLEANING AND MAINTENANCE

26

If you take the lens off your camera, you can see the mirror and look up into the

pentamirror assembly.

In addition to the brighter, clearer view of the scene, many photographers choose

SLRs because they like to block out the rest of the world with the camera so that

they can fully concentrate on the image in the viewfinder. is is much harder to

do with the inferior viewfinder or LCD viewfinder on a point-and-shoot camera.

TIP: Watch the Mirror Move

With the lens off and the power on, you can press the shutter button and ac-

tually see the mirror flip up and, if you’re quick, see the shutter open behind it.

However, before you do this, know that shooting the camera with the mirror

off will expose your sensor to dust. Don’t do this outside or in a dusty room

(or at all, if you don’t want to take chances). Better still, if you have a friend

with an SLR, try it with their camera when they’re not looking.

Cleaning and Maintenance

At a fundamental level, all cameras are the same: A lens focuses light onto a re-

cording medium. Because the recording medium is light-sensitive, it must be kept

in a lightproof box. A shutter in front of the recording medium allows for control

of when the sensor is exposed and how long the exposure will last. Cameras have

worked this way since the beginning of photography in the 1850s, and while all

sorts of new technologies have ...