Telescopes and cameras use diverging and converging lenses to focus images.
Lenses are used in many applications and it is common to find both converging and diverging lenses in the same object. The most common everyday use for diverging lenses is glasses for nearsighted people. But recreating this requires complex machinery to measure focal points and to prepare the lens itself. There are several uses for diverging lenses which can be recreated, although they are not going to achieve the same effect as a specially-engineered item.
Instructions
Telescopes and Binoculars
1. Place one diverging lens in front of a converging lens.
2. Encase the lenses in a tube to shut out any additional light.
3. Adjust either lens to focus the telescope on an object.
4. Look through the telescope to see a magnified image of the object. The diverging lens collects the light from the object, spreads it to make the object larger before it is focused by the converging lens, so it can be seen by the human eye. This is why if you look through a telescope the wrong way, the object gets smaller.
Cameras
5. Place a diverging lens in between to converging lenses.
6. Put a shutter holding camera film behind the lenses.
7. Encase the lenses, shutter and film to shut out additional light.
8. Adjust the distance between the lenses to focus the image.
9. Open the shutter to project an image onto the camera film.
Ray Diagrams
10. Set up a screen with three thin slits in front of a light bulb.
11. Place a diverging lens in front so when the bulb is on the light, it will shine through the three slits and onto the lens.
12. Turn on the light bulb and turn off all additional lighting.
13. Observe the three rays of light separating as they pass through the diverging lens. This is a very important experiment to learn about the wave nature of light and about the focus point of light, a technique used in telescopes and cameras.
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