Photographers sometimes take pictures and add a filter to the lens. What is this for?

This is to get different effects. Here is a brief introduction to the filters commonly used by photographers.

1. The more important anti-ultraviolet lens in the film age is irrelevant in the digital age, because filtering does not filter ultraviolet rays, which is not important for digital image sensors.

2.ND gray mirror, used to weaken the light when the light is too strong, thus slowing down the shutter speed. Some special occasions will need a slow shutter, such as shooting waterfalls.

3.CPL circular polarizer is used to reduce the influence of reflected light. For example, some leaves in the sun may turn pale because of reflected light. After adding CPL, the influence of reflected light can be reduced by adjusting the angles of two lenses of CPL.

4. Special function filters, including starlight mirrors, color filters, gradient mirrors, etc. , not commonly used.