Exposure control technology

Exposure control adjusts the color, so that the color can better simulate the large dynamic range of the eyes, while still being suitable for the color range that can be rendered. Let me introduce you to the skills of exposure control, hoping to help you!

1. Skills of exposure control: What is the addition formula and what is its significance?

After research, the researchers got a simple formula to control exposure, which is the famous addition formula:

AV+TV=EV=SV+BV

Where AV is aperture value, abbreviated as AV value, TV is shutter value, abbreviated as TV value; SV is the film sensitivity value, referred to as SV value; BV is the brightness value; EV is called exposure value.

The addition formula embodies the principle and function of exposure measurement system, which is of great significance for designing exposure measurement system or using camera.

2. Exposure control skills: Try to talk about reciprocity law and its failure.

Reciprocity law means that the corresponding combination of shutter speed (exposure time) and aperture (exposure intensity) will produce the same result. That is, if the shutter speed is increased by 1 times and the aperture is reduced by half, or the aperture is increased by 1 times and the shutter speed is reduced by half, the exposure obtained is the same. This general effect is unchanged, and the reciprocity relationship in which the image surface illumination and exposure time can be adjusted each other is called reciprocity law.

The law of reciprocity is not always effective. Even if the exposure amount should be the same in theory, exposure in extremely bright light for a short time or exposure in extremely dark light for a long time will change the exposure effect. In other words, the law of reciprocity is only valid within a certain range, and beyond a certain range, the law of reciprocity fails.

3. Skills of exposure control: What are the photometric methods, advantages and disadvantages of illuminance measurement?

Measurement method: illuminance measurement is to measure the light projected on the object being photographed. When measuring, put the exposure meter on the milky white cover so that the photosensitive probe of the exposure meter points from the direction of the subject to the direction of the camera. This can objectively restore the brightness change of the scene.

Advantages: When the illuminance measurement results are used to control the drawing of X-rays, the surfaces of objects with different reflectivity can be objectively restored in the picture.

Disadvantages: When using illuminance measurement results to control X-ray drawing, it is often impossible to form the best effect of some scenes in the picture according to the creator's intention.

4. Skills of exposure control: exposure characteristics of different themes.

Brightness measurement is to measure the light reflected by an object. When measuring, the opalescent light shield of the exposure meter should be removed so that the photosensitive probe of the exposure meter points from the camera direction to the subject direction.

The advantage is that you can subjectively show the surfaces of objects with different reflectivity in the picture, and measure which surface will form the best effect in the picture according to which surface when shooting. Its disadvantage is that some scenes cannot be objectively restored in the picture.

5. Exposure control skills: practical application

Different seasons: one exposure in winter and one exposure in summer.

The weather is different: one exposure is increased on a thin cloudy day and one exposure is reduced in summer.

Different altitudes: for every 2000m increase, the exposure will be reduced.

Different latitudes: the higher the latitude, the higher the exposure.

Shooting scenery: small aperture, large depth of field.

Portrait shooting: large aperture and small depth of field.

Take a commemorative photo: appropriately narrow the aperture.

Macro photography: Minimize aperture and increase depth of field.

Advertising photography: even calculate the aperture number and control the depth of field.

Sports Photography: Solidification, Dynamic Performance or Subsequent Shooting?

Stage photography: A specific shutter speed is required.

News photography: if you use flash, you need to synchronize the speed of the flash.

Show water in landscape photography: adjust it as needed.

6. Exposure control skills: What is the concept of exposure compensation, and what is the applicable occasion of exposure compensation?

There is a deviation between the actual exposure using the automatic exposure system and the photometric value measured by the photometric system. This function is called exposure compensation.

Suitable for the following occasions: the whole picture color deviates from the middle gray. In order to achieve special artistic effects. The contrast between the subject and the background is strong, and the subject area is small. There is an error in the exposure system.