Photography: How to make a film that keeps the sky blue without darkening the scenery?

There are two common methods: reducing exposure compensation and adding a polarizer in front of the lens.

1, reducing exposure compensation

Adjust the exposure compensation negatively by 1/3 to 1. Principle: When taking style photos, the brightness of the sky is generally higher than the ground, and the camera will average the exposure value after automatic metering, resulting in overexposure and whitening of the sky. By reducing the exposure compensation, the sky can be exposed normally and appear blue.

2. Adding a polarizer in front of the lens can filter polarized light.

Polarizer, also called polarizer, referred to as PL mirror, is a kind of color filter. The excellent function of polarizer is that it can 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. For example, in landscape and scenery photography, it is often used to show the texture of objects with strong reflection, highlight the scenery behind the glass, darken the sky and show blue sky and white clouds.

According to different mechanisms of filtering polarized light, polarizers can be divided into circular polarizer (CPL) and linear polarizer (LPL).