What is the concept of 18 shades of gray in photography?

18 shades of gray in photography

Second level meaning.

The first level of photography metering uses 18% reflectivity as the exposure reference value. (Because the camera Commonly used light metering systems use the gray of an 18-degree gray board as the benchmark value. However, when the measured value of a pure black subject or a pure white subject is compared with the 18-degree gray board, it will produce a huge difference. The error will cause the actual metered value to be overexposed or underexposed!) Reference website 1: /index.php?showtopic=34067 This website has real pictures, you will understand better after taking a look

How to measure Light.Method

First, make sure that the light hitting the gray board is basically the same as the light hitting the subject. Both should be of equal strength. For example, don't meter a gray slab exposed to sunlight while the subject is standing in the shade of a tree. If the subject is in the shade of a tree, meter the gray board in the same shade.

Secondly, we may notice that if the photographer's hand is projected on one corner of the gray board. If our subject is exposed to sunlight at this time, we need to make sure we are not measuring this shadow.

Third, the gray board we bought in the store measured about 8 inches by 10 inches, which was too large to fit in a camera bag. Don't be embarrassed, cut it in half or quarters, just keep a small piece in your camera bag. The size of the gray board is sufficient as long as it can measure light at close range when shooting.

Fourth, use a handheld light meter to read the gray board data. We can also use the built-in light meter in the camera to read the gray plate, and the effect is the same.

Fifth, even if our camera has an automatic exposure function, we can still use a gray board. If our camera provides the ability to lock the exposure reading, we can do the following:

First, read the gray plate data at close range and press the exposure lock.

Then, while locking this exposure in place, point the camera at the scene you want to capture and capture the image. If the light illuminating the scene is the same as the light read from the gray plate, then the exposure is correct.

Sixth, we may note that there is a similarity between the gray plate reading and the incident light reading. Indeed, they should both provide exactly the same recommended exposure. Both of them are very important for illumination. The light of the subject is measured. When we take incident light measurements, the white plastic cover on the light meter allows 18% of light to pass through, which is exactly the same as taking reflected light measurements on a gray panel. A gray board reflects 18% of the light that hits it. If the illumination light is the same, then the two readings should be the same.

Also, if you are using a handheld light meter (the one with a white ball like Shiguang 608), there is no need to use an 18-degree gray board, because it is equivalent to an 18-degree gray board!

The second layer is the current digital era (only applicable to digital cameras). It is used to customize the camera settings. The specific settings are different for each camera. The settings of the same brand are generally the same. .I won’t say much here. Just tell me your camera model and I can tell you how to listen.