What is metering? What are the main metering modes of the camera?

The so-called metering refers to the camera metering system (only continuous light source can be measured), or the process of measuring the reflected light brightness of the subject with a light meter. Metering is a prerequisite for correct exposure. Metering not only determines the tone, but also affects the color tone. Under different exposure modes, the color saturation presented by the object will also have different effects. The camera and its metering system are designed and manufactured according to the principle of Class V gray (18% reflectivity), and the metering position is the basis for determining the amount of exposure.

In the same scene, the exposure level is different if the metering mode is different. The larger the metering coverage area, the smaller the autonomy of the photographer, and the less likely it is to meet the special artistic creation needs; conversely, the easier it is to meet the special creation needs. High-level photographers prefer spot metering.

Multi-zone metering, also known as evaluative metering (Canon), composite metering (Nikon), honeycomb metering (Minolta), weighing metering, and one of the camera metering modes. Multi-zone metering is to divide the photographed picture into several areas with primary and secondary, such as zone 3, zone 5, zone 9 (Adams exposure method), zone 11, zone 14, zone 21, zone 45, etc. The camera's metering system will automatically measure the brightness of the scene in each area, and use fuzzy logic to perform weighted synthesis based on the priority to calculate an optimal exposure. The characteristic is that the image is general and lacks individuality. Evaluative metering is more accurate for forward and front metering.

Center-weighted metering, also known as center-weighted metering, is one of the camera's metering modes. Center-weighted metering is a metering mode that focuses on the center of the screen. The metering position is in the center of the screen, and the metering range is large, accounting for about 70% of the entire screen area (in a circle with a diameter of about 12 mm in the center of the screen).

Central partial metering, one of the camera metering modes. Central partial metering is a metering mode that focuses on the central part of the screen. The metering position is in the center of the screen, and the metering range is only partial, accounting for about 8%-10% of the entire screen area (8.5% for Canon EOS-3).

Spot metering is a metering mode based on a certain point in the scene. The metering range is extremely small, accounting for about 3% of the entire screen. Spot metering only measures one point to make the correct exposure regardless of the remaining 97%. The advantage of spot metering is that the light receiving angle is only 1°-3°, and it is not affected by light other than spot metering. The advantages are: independence, convenience, high precision, and full of personality; it can not only meet the general exposure needs, but also meet the special artistic creation needs. The disadvantage is that it is difficult to use spot metering, but the key is to choose the right metering spot. Spot-measuring bright parts will lead to underexposure; spot-measuring dark parts will lead to overexposure. The method is to find V-class gray (18% reflective objects) in the scene, such as gray rocks and concrete walls. Secondly, select and measure important positions of the subject (such as the face in portrait photography) with spot metering.

Multi-point metering. The so-called multi-point metering is a camera metering mode in which multiple metering points are selected and the average value is taken. It is not advisable to measure only one point when shooting scenery and night scenes with complex lighting. Photographers need to have the underlying consciousness of "average" and "take the center" in their minds. If you measure two points (commonly known as light and dark metering), you can measure one point each at the brightest and darkest, or half-bright and half-dark places. If you measure four points, you can select two points in the bright part (high light, medium light, low light), and select two points in the dark part (light black, medium black, deep black).