Laza
註冊: 2005-12-21
上載我的肖像
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 Re: CPL勁深入問題 Post time: 10 月 21 日 |
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I'll give it a try to recall my Form 5 - Form 7 Physics....Feel free to correct me if there is anything wrong or incomplete.
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Optics - its basic principle
What is a light ray?
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Each light ray is an oscillatating (sinusoidal) electromagnetic wave, travelling in one direction, and its amplitude is traversing (oscillating) in a perpendicular direction. You can imagine it as a very thin ruler, on which a sine wave is drawn, and the ruler could fly around (incl. towards the camera lens) in all random direction.
What is light scattering?
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Imagine infinite number of such light rays are going into your camera lens in all kinds of direction, this randomness of direction is called "scattering of light".
How do polarizer work?
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Then comes a polarizer, which is actually a piece of glass of optical grade, and the molecular structure (or alignment) of it is such that it only allows light rays of a single direction to pass through. Imagine a metal grille of a number of vertical bars of very thin space between them, it would only allow light rays travelling on a vertical plane to pass through. All other light rays travelling on a plane other than vertical plane (i.e. horizontal or oblique) will be screened (i.e. filtered) out.
The effect of Polarization
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This filtering effect is called polarizing effect, and it could effectively filtering out some of the glare, and most amazingly, the reflection of a water surface or glass surface, allowing you to take an image of a water surface or glass surface free of reflection.
Hope my amateur physics lesson is easy enough to understand.
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