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Wow! Lots of interest in this topic!
One of our members who has made a close study of optics, recommends a very lightly colored polaroid for gliding. Particularly interesting points being: * a dark colour simply causes the eye to open wider to let in an appropriate 'amount' of light. When opened wide the eye is very susceptible to stray light coming from the side of the lenses, and the depth-of-field is dramatically reduced. Keeping the eye small ensures that maps, instruments and long distance focussing are likely to be much easier. * be certain that the lense stops UV (some offer little resistance!). The lenses should be large in size to maximise the UV blocking. * Sure, polaroid may have a problem under some canopies . . but this will be well known for that particular craft. Question for those advocates of the SunTigers (unlikely to be available here): Have you compared them to polaroids with similar colour? (perhaps SunTigers are available as polaroid too?) Cheers, Jim Kelly Australia. |
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Anyone able to comment on Polaroid vs SunTigers?
"Jim Kelly" wrote in message u... | Wow! Lots of interest in this topic! | | One of our members who has made a close study of optics, recommends | a very lightly colored polaroid for gliding. Particularly interesting | points being: | | * a dark colour simply causes the eye to open wider to let in an | appropriate 'amount' of light. When opened wide the eye is very | susceptible to stray light coming from the side of the lenses, and | the depth-of-field is dramatically reduced. Keeping the eye small | ensures that maps, instruments and long distance focussing are | likely to be much easier. | | * be certain that the lense stops UV (some offer little resistance!). | The lenses should be large in size to maximise the UV blocking. | | * Sure, polaroid may have a problem under some canopies . . but this | will be well known for that particular craft. | | Question for those advocates of the SunTigers (unlikely to be | available here): Have you compared them to polaroids with similar | colour? | | (perhaps SunTigers are available as polaroid too?) | | Cheers, | | Jim Kelly | Australia. | |
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Thanks for your comments Henryk and Todd,
Looks like we three agree on not using *dark* sunglasses! Cheers, Jim Kelly "Henryk Birecki" wrote in message ... | Jim, | | there is a big misconception in what you wrote. For polaroids to be | polarizing they have to absorb 50% of light, and then there are more | efficiency losses. Sun Tigers are about 50% or more transparent | (integrated intensity) so are likely to be "brighter" than polaroids. | | In addition to spherical aberrations that you refer to talking about | depth of focus there is also chromatic one. Suntigers shrink the | optical bandwidth effectively reducing chromatic aberration. | | Using Polaroid glasses and liguid crystal displays is another trick to | be mastered as the latter also rely on polarized light. | | Cheers, | | Henryk Birecki | | "Jim Kelly" wrote: | | * a dark colour simply causes the eye to open wider to let in an | appropriate 'amount' of light. When opened wide the eye is very | susceptible to stray light coming from the side of the lenses, and the | depth-of-field is dramatically reduced. Keeping the eye small ensures | that maps, instruments and long distance focussing are likely to be | much easier. | | |
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