How to measure light accurately

Effective measures for correct photometry

Whether the exposure is correct or not has a decisive influence on the picture quality. According to the characteristics that the performance of camera photometry device mostly takes average brightness, the effective measures and essentials to implement correct photometry can be summarized into four ways.

1, use of reference light.

The reflectivity of the object measured by the camera is 18% gray. You can find a piece of medium gray cardboard in front of or next to the object and make it face the camera. The camera lens is aimed at the gray board to fill the whole picture for photometry. After exposure with the exposure value, you can basically get a photo with accurate exposure.

2. Alternative photometry

In the absence of gray board, you can also use your arm instead of gray board for photometry. The reflectivity of the arm is about 20%, which is basically close to 18% gray board. When shooting, first measure the light on the arm, and then use the measured exposure value to adjust the exposure according to the actual situation.

3. Close-range photometry

When measuring light, the camera should be as close to the object as possible. This method can narrow the measurement range to a certain part of the object, effectively eliminate the interference of other parts, and the measurement results are more realistic. Close-range photometry can ensure that the photometry system of the camera is basically the same as the light receiving situation of the photographed object, and can measure the brightness value of key parts, so the exposure combination obtained is more accurate and credible.

4. Give priority to measuring important parts of the subject.

When shooting scenes or people with large contrast between light and dark, exposure should be made according to the brightness of their important parts when measuring light, for example, when shooting portraits with backlight, exposure should be made according to the brightness of people's faces.