What's the difference between grey mirror and polarizer in SLR?

1, the medium gray mirror is used to reduce the amount of light entering and play the role of sunglasses;

2. Although the polarizer can also reduce the luminous flux, it can reduce the reflected light more obviously and filter the light. Sometimes, polarizers can be used instead of gray mirrors.

The polarizer is made of two layers of glass with a layer of glass sandwiched between them. Directional crystals are made into thin films, and these crystals are arranged in sequence. The polarizer is installed on a rotatable mirror frame, and the optical axis is polarized at high speed by rotating the mirror frame.

Polarizer and gradient gray are similar when used to darken the sky, but the principle is completely different. The polarizer only allows light perpendicular to the off-axis direction to pass through, and light in other directions cannot pass through. When rotated to a certain angle, the light from above in the sky will pass less, which can highlight the effect of blue sky and white clouds. In addition, the biggest use is to resist the reflection of the surface of the object being photographed, such as glass, water surface, metal plate and so on.

Polarizers can weaken or eliminate polarized light, and at the same time improve the color saturation of images to varying degrees. In color landscape photography, the use of polarizer has been widely concerned. By shooting the still life of flowers, you can also get colorful and clear color masterpieces.