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yellow lens "polarized" night vision glasses, as seen on TV

yellow lens "polarized" night vision glasses, as seen on TV

yellow lens "polarized" night vision glasses, as seen on TV

(OP)
Well, I bought a pair of the yellow/amber Tac Glasses Night Vision at Walmart. The package clearly states they are polarized.
I don't think they are, first because they don't do much of anything for glare, and second because they don't go very dark when rotated 90° while wearing real polarized fishing glasses.

Should polarized amber/yellow lenses get super dark when rotated 90 degrees and looking thru regular polarized sunglasses?

RE: yellow lens "polarized" night vision glasses, as seen on TV

Can't think of any reason why they wouldn't. If nothing else, if you can pop out one of the lenses and rotate it against its mate and there is no darkening, then it's definitely BS.

Note that the manufacturer does not claim polarization: https://www.tacnight.com/

Note also, one of the comments on the Walmart product page says the same https://www.walmart.com/ip/Bell-Howell-Tac-Glasses...

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: yellow lens "polarized" night vision glasses, as seen on TV

I think if they are not good polarizers it won't get 'very' dark but should darken noticeably. You can also try looking at an LCD screen and rotate them 90 degrees. If you don't see any noticeable change then they are not. If the change is just slight then maybe from a marketing standpoint they are polarized but from a practical standpoint they are just poor polarizers.

Han primo incensus

RE: yellow lens "polarized" night vision glasses, as seen on TV

Tmoose,

A polarizer on its own, is a neutral density filter. On a camera, they attenuate a full F-stop. Is this a good idea for night vision?

--
JHG

RE: yellow lens "polarized" night vision glasses, as seen on TV

(OP)
Hi Drawoh,

Yes indeed, I was concerned with what a light colored (yellow) polarized lens would do. In the TV ads they looked great.
I figured if I got them from Walmart and they proved to be crap they'd be a lot easier to return than by mail.
Plus they were cheaper, sort of.

I was remembering hearing that Edwin Land was promoting polarization to make night vision safer.
Turns out he was probably thinking about the opposing cars' headlights, not the windshield.
https://www.polarization.com/land/land.html

RE: yellow lens "polarized" night vision glasses, as seen on TV

Tmoose,

Polarized lenses reduce clear, as long as the glare is polarized. Sunlight is polarized. Are care headlights?

--
JHG

RE: yellow lens "polarized" night vision glasses, as seen on TV

I don't think there are any headlights that are polarized. And sunlight by itself is not polarized. Once the light hits a surface an angle greater than the Brewsters angle the reflection is polarized.

Han primo incensus

RE: yellow lens "polarized" night vision glasses, as seen on TV

"Once the light hits a surface an angle greater than the Brewsters angle the reflection is polarized"

That's for complete polarization, and only at Brewster's angle; on either side of that, you'll get partially polarized light.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: yellow lens "polarized" night vision glasses, as seen on TV

True, the degree of polarization goes up as the angle increases, up to and including Brewster's. But sunlight by itself is not polarized (ignoring that you can say that it is randomly polarized). That was what I was addressing more than polarization in general.

Han primo incensus

RE: yellow lens "polarized" night vision glasses, as seen on TV

IRstuff's first reply is a classic test to determine if lens are polarized.

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