Polarized Night Sunglasses (11001-1)

1) Fashion Metal sunglasses with 1.1mm Polarized lens;
2) Stainless steel frame
3) Meet CE and FDA and AS/NZS, the lens meet UV400 standard
4) Compatitive price with best quality in mass market;
5) Assorted colors for lens and frames;
6) More information for eyewear item please contact us NOW!

Packing: Each sunglasses packed with poly bag, 12PCS/inner box and 300PCS
Per export carton(78x23x43cm, about 9kg);

How do I know if mine are polarized?

Very easily done. Just look through the glasses at the reflection of any object on a window panel (but not at yourself! You have to look at an angle to the glass). Then, turn the sunglasses around as if they were the hands of a clock facing you. If the intensity of the reflection doesn't change with respect to what you see through the window, they are not polarized. Or you can use as your target image any of the numerous other examples of linear polarization mentioned in this web site, read on!

I still don't understand, why are polarized sunglasses better than normal dark sunglasses?

Normal sunglasses decrease the intensity of everything by the same amount. Polarized sunglasses can selectively eliminate the reflection from light coming from above the water surface.

Then, could polarized glasses be crystal clear?

Nope, they will always decrease the intensity of unpolarized light by at least half. In practice somewhat more because of losses in the material. They come in all shades from light gray (only polarizing) to very dark (polarizing plus black tint), and also light sensitive (photochromatic). You can even find sunglasses with darkness adjustable by the user.

Do polarized sunglasses help see fish and rocks below the water surface?

Yes. First, if there is glare, they help a lot by reducing its blinding effect. Second, even without glare they selectively reduce other reflections from objects above water, including clouds and even the sky (the reflected sky gives most of its blue color to the sea). Finally, light coming from under water is slightly polarized in the vertical plane (polarized on transmission). The end effect is that the water seems darker but more transparent! But remember, it only works if you look at the water at some angle and not straight down.
Does it matter the time of the day?

Yes. Maximum polarization is obtained when the sun is at about 37 degrees from the horizon (in theory 100% polarization at the Brewster angle). If the sun is very low or very high the sunglasses will be of little help in filtering the glare in calm seas. A rule of thumb would be that polarized filters limit the glare from calm waters for a sun altitude between 30 and 60 degrees (but see next question). Anyway, it should be stressed that polarization won't help in looking directly at the sun (except in decreasing the overall intensity of everything by half).
Does it matter the choppiness of the sea?

Yes. When the sea is ruffled the sun reflection becomes the familiar glitter, an elongated pattern of shimmering water stretching towards the sun. Because different parts of the glitter are reflected from different wave slopes, the degree of polarization varies from place to place. In those conditions the sunglasses will also help for high or low suns and the benefit will depend on where you are looking. As a side note, the width and length of the glitter together with the altitude of the sun can be used to compute the height of the waves without ever getting close to them!