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Understanding Basic Optics
Lenses
Complex Lenses
Simple Lenses
What are lenses?
- Lenses
bend light in useful ways. Most devices that control light have
one or more lenses in them (some use only mirrors, which can do
most of the same things that lenses can do).
There are TWO basic simple lens types:
- CONVEX or POSITIVE lenses will CONVERGE or FOCUS light and can form an
IMAGE
- CONCAVE or NEGATIVE lenses will DIVERGE (spread out) light rays
- You can have mixed lens shapes too
What are simple or complex lenses?
- Simple
lenses can't form very sharp images, so lens designers or optical
engineers figure out how to combine the simple types to make complex
lenses that work better. We use special computer programs to help
us do this because it can take BILLIONS and BILLIONS of calculations.
Camera lens:
- This complex lens has 6 simple lens elements
Zoom lens for home video camera (13 elements)
- A professional TV zoom lens used to broadcast sports could have
40 elements and cost over $100,000
Magnifying Glass: A simple optical device
- This
diagram shows how a magnifying glass bends light rays to make
things look bigger than they are. Many devices use the same basic
idea of bending the light to fool your eye and brain so light
LOOKS like it came from a different (usually larger or closer)
object.
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