What changes in a camera to let you zoom in more?

Question

The lens moves forward, doesn't it? But then, why is the image magnified 10 times by such a small change in distance?

Answer 1

It's magic.

Depending on the camera, you have digital and optical zoom. Optical zoom is best, because it doesn't mess with the image. When you digitally zoom an image, everything gets compressed, or put closer together in a picture (trees will look closer to a mountain). Here's quite a bit more information: http://www.photoxels.com/article-optical-digital-zoom.html

In fact, here's an image showing the difference between the zooms: http://www.cambridgeincolour.com/tutorials/image-interpolation.htm#digital-zoom

Answer 2

You increase the "focal lenght" in the camera in order to zoom in more.

"FOCAL LENGTH AND IMAGE SIZE.–When you photograph the same object at the same distance, a lens with a long-focal length produces a larger image than one with a short-focal length. In effect, the longer focal-length lens magnifies or brings the subject closer to the camera without changing the camera-to-subject distance (fig. 1-19). For example, a man 6 feet tall stands at a distance of 25 feet from three cameras, one equipped with a 6-inch lens, one with a 12-inch lens, and one with a 24-inch lens. The 6-inch lens produces a 1 1/2-inch image of the man. The 12-inch lens produces an image that is 3 inches high. The 24-inch lens produces a 6-inch image. From this example, it is obvious that the longer the focal length of the lens, the larger the image size of a given object from a given lens-to-subject distance"