The Canon EOS Digital Rebel XS/1000D Companion

Chapter 5. Photography 101

THE FUNDAMENTAL THEORY OF EXPOSURE

In this chapter, we'll take a break from cameras and computers and focus on basic photo theory. In the old days of manual cameras, you couldn't learn to shoot without certain fundamental knowledge. With today's automatic cameras it's possible to take great photos without having the slightest notion of how different parameters affect your image. However, you'll most likely find that shooters who do understand the basics have a broader creative palette to work with and can push their photography further. We'll be using the concepts covered in this chapter through the rest of the book.

In Chapter 2 we took a quick look at the anatomy of your Rebel XS, and you learned something about the architecture of an SLR camera. In that discussion I mentioned the image sensor in your camera. As you already know, in a digital camera, the image sensor takes the place of a piece of film and is the mechanism by which the camera can "see" an image.

The image sensor is a chip that is mounted parallel to the back of the camera so that the light focused by the lens hits it head-on. In the Rebel XS, the image sensor is the same size as a piece of APS film.

Figure 5-1. The image sensor in your Rebel XS is a large silicon chip with an imaging area ...