Effect of polarising filters

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Peter Copestake
Posts: 339
Joined: Sun Feb 11, 2007 2:23 am
Location: Colne, Lancashire

Effect of polarising filters

Post by Peter Copestake »

During what I remember as a very brief summer I sent away for a pair of clip-on sunshades. Very thin tinted plastic, they surprised me by giving the impression of separating the planes of a middle-range view in the garden - foreground, middle and more than 20 feet, say in a way that I have never noticed with tinted specs. Would that be an effect of the plastic polarising the light or interaction with artificial lenses in my eyes (cataract replacements), do polarising filters have any similar effect in photographs/film or video? My specs are not 'strong' but I do need prisms in them to correct double vision. My daughter needs VERY strong specs (Very short-sighted) but no prisms and she got the same effect. Any ideas? Seems like one for Tom! Happy New Year everyone.
Peter.
Peter Copestake
tom hardwick
Posts: 876
Joined: Mon Jan 29, 2007 9:59 am

Re: Effect of polarising filters

Post by tom hardwick »

These clip on shades ARE polarised lenses presumably Peter. If so, then they're polarising the wavelengths of light, and light reflected off different surfaces does behave in different ways. Polarised lenses let you 'look into' a pond, whereas reflected light of grass appears to be unchanged.

The different reflectivity of surfaces might be giving you the effect you describe, but I can't be sure. I wouldn't have thought the plastic lenses in your eyes had anything to do with it, as they're designed to replicate your original lenses as far as possible.
Peter Copestake
Posts: 339
Joined: Sun Feb 11, 2007 2:23 am
Location: Colne, Lancashire

Re: Effect of polarising filters

Post by Peter Copestake »

Thanks, Tom. New question posed on this forum.
Peter.
Peter Copestake
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