What's the difference between subtracter, gradient mirror and polarizer? What are their functions?

1, the reducing mirror is also called medium gray density mirror, neutral grey mirror or grey mirror and nd mirror for short, and its main function is to reduce the amount of light entering the camera. The reducing mirror plays a very important role in a good photo.

The role of reduction mirror: reduction mirror can bring more exposure means to your creation, turn day into night and expand creative space; It can "resist" a lot of scattered light. When shooting in rainy days, the color saturation of the picture can be improved, and the reduction of scattered light can make the picture look more transparent.

2. Gradient mirror, also known as [GND filter], is one of the most important filters in photographic art creation. It can be divided into gradient mirror and gradient diffusion mirror, and can be divided into soft gradient and hard gradient in gradient form. "Soft" means a large transition range, and vice versa, it means a small transition range, which should be chosen according to the creative characteristics.

The function of gradient mirror: the gradient mirror has a gradient effect on the photo; Many photographers will add a brown gradient lens when shooting cloudy and cloudy subjects to express nostalgia and moodiness. You can even use two color gradient filters at the same time to make the upper and lower parts of the photo appear different colors, making the photo more picturesque.

3. Polarizer, also called polarizer, referred to as PL mirror, is a kind of color filter. The achromatic function of polarizer is to selectively let the light that vibrates in a certain direction pass through, and it is often used to eliminate or weaken the strong reflection of non-metallic surface in color and black-and-white photography, thus eliminating or reducing the light spot.

Function of polarizer: Polarizer can effectively improve color saturation and contrast, because polarizer can absorb stray light reflected by fog or dust in the atmosphere in all directions, thus making the photographed image more pure.

Extended data:

The filtering function of the thinning mirror is non-selective, and the thinning ability of light with different wavelengths is equal and consistent; In other words, the antireflection mirror will not have any influence on the color of the original object, but also can truly reproduce the contrast of the scene (essentially, due to the process, the color temperature will still produce a small amount of deviation).

The gradient mirror has a gradient effect on the photo, and the filter only works on one side, and the other side has no effect on the photo. According to the purpose, the common gradient lenses are gray gradient lenses, blue gradient lenses, taupe gradient lenses, orange gradient lenses and so on.

The mechanism of filtering polarized light is different. Polarizers can be divided into circular polarizer (CPL) and linear polarizer (LPL), and their functions are the same.

References:

Baidu Encyclopedia-Restore Mirror Image