As with human clothes and accessories in general, polarized shades come in a variety of styles, a variety of colors, lens shapes, lens sizes, and frame configurations. Following are descriptions of some of the many that are sold by various companies. It should be realized that most of them are available in colors- both for the lenses and for the frames- other than the ones indicated. (Also note that darker lenses provide a higher degree of polarization.)
Polarized sunglasses differ from traditional ones in certain ways. The latter reduces the entire field of vision, thus making it difficult to distinguish subtle details; whereas polarized shades block out only selected rays. In other words, the benefit of these sunglasses is twofold: The cut down unnecessarily bright light while at the same time enabling the wearer to see subtle contrasts.
One important application of the effects of polarized light can be seen in cameras: Without a polarizing filter, the camera picks up mirror- like reflections in water, on glass, and the like, making a photograph in which such surfaces are prominent appear like a double exposure. A polarizing filter placed over the lens absorbs such reflections, making the photograph appear much clearer.
The reason it works this way is because light from a reflection is naturally polarized in the direction of that reflection; the optical grain is oriented perpendicular to that direction, thus cutting off the light coming from the reflection. Similarly, the filter can reduce the brightness of a sunny sky that is particularly noticeable on the horizon.
Lenses can be made from three materials- glass, polycarbonate, and acrylic. Of these, glass is the heaviest and most expensive, so it should not be worn for sports, while acrylic provides the least amount of distortion. The color of the lenses should also be taken into consideration when buying a pair for fishing: Gray is best for fishing on the open water, for example.
Polarized sunglasses differ from traditional ones in certain ways. The latter reduces the entire field of vision, thus making it difficult to distinguish subtle details; whereas polarized shades block out only selected rays. In other words, the benefit of these sunglasses is twofold: The cut down unnecessarily bright light while at the same time enabling the wearer to see subtle contrasts.
One important application of the effects of polarized light can be seen in cameras: Without a polarizing filter, the camera picks up mirror- like reflections in water, on glass, and the like, making a photograph in which such surfaces are prominent appear like a double exposure. A polarizing filter placed over the lens absorbs such reflections, making the photograph appear much clearer.
The reason it works this way is because light from a reflection is naturally polarized in the direction of that reflection; the optical grain is oriented perpendicular to that direction, thus cutting off the light coming from the reflection. Similarly, the filter can reduce the brightness of a sunny sky that is particularly noticeable on the horizon.
Lenses can be made from three materials- glass, polycarbonate, and acrylic. Of these, glass is the heaviest and most expensive, so it should not be worn for sports, while acrylic provides the least amount of distortion. The color of the lenses should also be taken into consideration when buying a pair for fishing: Gray is best for fishing on the open water, for example.
No comments:
Post a Comment