How to use the built-in exposure meter of digital SLR camera?

Modern cameras have metering devices, which can also be called exposure meters. The light metering device is connected with the aperture and shutter of the camera to form the exposure system of the camera.

1. If automatic modes such as aperture priority, shutter priority or program combination are adopted, the exposure system belongs to automatic mode; If the aperture and shutter values are manually adjusted, the values of the metering device are for reference only and will not be linked with the aperture and shutter.

However, the digital camera also has a function closely related to exposure, that is, automatic exposure. If automatic sensitivity is turned on, it will be linked with aperture and shutter. Even if you manually adjust the aperture and shutter, turn off the automatic sensitivity. Pay attention to this!

3. At present, there are three kinds of camera metering modes: matrix (full-screen balanced evaluation, suitable for shooting landscapes and large scenes, suitable for most occasions) and focus (mainly metering the central subject, with different camera coverage, accounting for about 50% in the center of the picture; Suitable for shooting scenes with prominent subjects, but also for most occasions) and spot metering (for small subjects, the coverage range is 6- 10mm, which is suitable for occasions where the light between the subject and the background is quite different, such as large black or white background, stage photography, etc. ).

4. The "horizontal axis" you mentioned is only an exposure value indicator to indicate whether exposure value is correct.

5. Under normal circumstances, the cursor of exposure value table is at position 0, indicating that the exposure combination currently used is accurate exposure; However, due to the influence of ambient light changes, such as forward light, backward light, diffused light, reflected light and so on. The illuminance of the light-receiving object will also be different, which is what you said. Sometimes the exposure value indicator is 0, but the picture may not be satisfactory. This is because the metering device of the camera belongs to the reflective metering device. Although the measurement is convenient, the numerical value is easily influenced and inaccurate. Most professional photographers will use a professional exposure instrument with incident metering function to measure light. I won't talk about it here.

6. In order to make up for the inaccuracy of metering devices sometimes, cameras are basically equipped with "exposure compensation" function. Simply put, it is to fine-tune the measurement value by adding and subtracting. I won't talk about it here.

You'd better read the manual of the camera carefully several times, and most of them can find the answer.