Which is more practical, subtracter or polarizer?

Abstract: Variable-diameter mirror is also called medium gray mirror, medium gray mirror or grey mirror and Nd mirror for short. 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. Reducing the mirror can bring more exposure means to your creation, turn day into night and give full play to the creative space. So, which is more practical, the subtractor or the polarizer? Let's take a look and find out! Difference between reducing mirror and polarizing mirror

1, different functions

Reduce mirror: Reduce mirror can bring more exposure means for your creation, turn day into night, and give full play to creative space.

Polarizer: According to the different mechanism of filtering polarized light, polarizer can be divided into two types: circular polarizer (CPL) and linear polarizer (LPL) with the same function. The function of PL mirror is to filter the reflected light and increase the imaging contrast.

PL mirror can also effectively weaken or eliminate the reflection of nonmetallic surface, which is a typical polarized light (the light reflected by metal surface is not polarized light, and the polarizer has no effect on it). By adjusting the polarizer, this part of the reflection can be filtered out, thus improving the imaging quality of the subject and the clarity of the picture.

2, the principle is different

Retarder: Many times, due to the intensity of external light, we can't get enough shutter time, so we can't realize our photography intention. For example, when shooting water in the wild, we hope to use the shutter of 1 sec to make the water flow appear soft, like cotton.

However, due to the strong light, that is, using the minimum aperture of the camera and the minimum ISO shooting, the shutter speed is still around 1/30 seconds. At this time, the only way is to use one or even two ND8 lenses to weaken the light entering the lens.

Polarizer: A filter that can filter polarized light is called a polarizer. Ordinary polarizers are called linear polarizers (PL mirrors). Install the polarizer in front of the lens and carefully rotate the polarizer to minimize or even eliminate harmful glare, so that the photos you take have no glare. If you shoot the blue sky, it will appear bluer and darker.

The polarizer not only filters out polarized light, but also filters out the unpolarized light that vibrates in the same direction as the polarized light. Therefore, after using a polarizer, it is generally necessary to increase the exposure of more than one step.

3. Different classifications

Reducer: rotatable half mirror [R-HALFND], half transparent and the other half ND4. 75% or equivalent to the second-order aperture of ND4 side cutting light. The lens is installed in a rotatable frame and can be adjusted horizontally. This kind of reducing mirror is used to deepen the tone of the sky or the intensity of its chemical light is very different.

Polarizer: Common circular polarizers include polarized driving glasses, outdoor sports glasses, golf glasses, circular polarizers and linear polarizers.

Which is more practical, subtracter or polarizer?

The subtracter is just two polarizers stacked together. Compared with a polarizer, the subtractor can filter out the light in a specific band/angle, and the subtractor can filter out all the light passing through the filter. Both are necessary for camera shooting. The former is to eliminate reflection and improve contrast and tone, while the latter is simply to reduce light, so that long exposure photography will not be overexposed. ND filter is often used in camera shooting where shutter angle, aperture and exposure index must be strictly required to ensure correct exposure.