Course of exposure method in digital photography area

Lead: The regional exposure method was put forward by Ansel in 1930s. Adams and Fred? Archie proposed. This theory establishes the standard process of photographic exposure to ensure accurate exposure in any environment, including scenes such as backlight and maximum light ratio, which can completely deceive the camera metering system. This article will introduce you to this method and explain how to use it in your own photography.

The design idea of modern camera with built-in exposure meter is to provide users with an exposure reading that is applicable in most cases. However, when you face an unconventional environment, such as a scene with both bright and dark areas, the camera exposure instrument cannot work effectively. At this time, it's time for the regional exposure method to show its talents, which can help you get not only correct but also charming exposure results. Although the area exposure method was originally established based on black-and-white film photography, it is also suitable for black-and-white or color film, negative or reverse film and digital photography.

Advantages of area exposure method:

1. Even in the face of extremely complicated scenes, accurate exposure can be easily obtained.

2. The hue and dynamic range of the scene can be accurately evaluated before shooting.

3. Know when to use the medium gray filter.

4. Learn how to choose to shoot around the exposure range.

5. Know how to use fill light to get correct exposure.

Neutral ash

The function of the camera's built-in exposure meter is to provide users with exposure readings suitable for most situations. In other words, the camera will regard all scenes as things with neutral reflectivity (18% reflectivity) and use this as the basis to generate images, which are neutral gray (the reading is between pure white and pure black).

Therefore, if there are many bright parts in a scene, the image restored by camera automatic exposure will be darker than the actual one, that is, underexposed. On the contrary, a scene dominated by dark areas will be brightened by the camera, that is, overexposed.

Human eyes can see colors. The reflectivity of most colors is around the average, which is equivalent to the light reflected by neutral gray, that is, the middle tone. Understanding alto is the basis of learning area exposure method.

Basic concept of area exposure method

The area exposure method divides a scene from black to white into 10 parts, sometimes called 9 or 1 1 parts. Each one is an area. Each area differs from the previous area by 1 exposure. All areas are marked with Roman numerals, and the middle area (neutral gray) is located in the fifth area, that is, the V area.

For digital photographers, we usually only pay attention to the area between area 3 and area 7 (area 3 to area 7). The darkest part of the scene will fall into zone III, and the brightest part will enter zone VII. The part beyond this range will be regarded as pure black or pure white, and no details will be kept.

When the camera is aimed at the scene with accurate average reflectivity and photometry, the image restored according to the average reflectivity can be obtained. If you increase the aperture by 1 or lower the shutter by 1, the image will be overexposed by 1. If you reduce the aperture of 1 or increase the shutter of 1, the image will be underexposed 1.

First of all, we should think that the middle key is located in the V region. If the overexposure is 1, it is the VI region. If the underexposure is 1, it is zone IV.

Colors of different areas

As you can see from the above picture, the color with average reflectivity can be accurately restored in the V area. Accurate restoration means that the color in the photo is consistent with what you actually see. These colors include green grass or leaves, big red flowers, clean blue sky and 18% gray.

The color of area VI is lighter than that of area V, including pure yellow, bright pink, baby blue and baby powder.

The colors lighter than the six districts are located in Zongqi, including white snow, white clouds, white fog, white smoke, white frost and white sand.

Colors that are slightly darker than the midtones are located in fourth area, including tree trunks and deep blue sky.

Area III is dark in color, with black puppies, black shoes, shade and coal. In digital photography, accurate exposure (technology) in the usual sense refers to the exposure of intermediate tones without overexposure of highlights. The reason why it is emphasized that there is no overexposure in high-light areas is that overexposure in high-light areas damages details more seriously than underexposure in dark areas.

Therefore, if the illumination ratio of a scene is beyond the dynamic range of the photo, you need to choose whether to keep the highlights or the dark parts. And unless the highlight area is small and there is nothing worthy of attention, you should try to keep the highlight area. Overexposure of highlights usually makes people feel that there is something missing in the photo, while underexposure of shadows is more acceptable and sometimes has a unique effect.

In order to accurately expose the halftone, it is necessary to sample the object with halftone color. Adjust the camera parameters until the exposure indicator bar of spot metering results is located at? 0? Then make sure the highlights are not overexposed, and you can shoot.

In the above picture, yellow is located in the VI area. Pure yellow is usually located in the VI area because it reflects more light than middle tones. Bright orange can also be considered in the sixth area, or maybe it is only 0.5 level brighter than the fifth area. ..

Saturated orange is a midtone color, so it is located in the region V. True red is usually in the region V unless it is obviously dark or bright. Here, the red color is located in zone IV, which is darker than the true red color. The floor is very bright, located in the seventh district.

In this photo, half of the sky is in the middle tone, located in the V area, and the sky near the ground gradually becomes shallow and enters the VI area. The sky began to deepen at the top of the picture and entered the IV area.

Usually grass and leaves are in the middle tone, unless they look obviously dark or bright. In this photo, the grass happens to be the V area.

The tree in the background is dark 1, so it is located in the IV area. The cloud is white and retains details, so it is the seventh district.

The road surface is darker than the middle 1 or 1.5, so it is located in Zone IV (or between Zone IV and Zone III).

In the above picture, the sea level at the bottom of the picture is basically in the middle tone, so it is located in the V area. Looking up, the color begins to darken, so the sea level is near the IV area.

For the sky, the upper and right sides are middle tones, located in V area, darker down and left side, located in IV area (maybe a little brighter than IV area).

The right part of the lighthouse is brighter than the sixth area located in the seventh area. The dock itself is dark and has details, so it is located in Area III.

This photo is used to show that grass and leaves can have different shades and in which area they are located.

The grass on the left of the picture is in the middle of Zoen V, and the grass around the road is bright, which is located in VI area. The trees on both sides of the road are darker in color than in the middle, and are located in the IV area. The bushes in the background are very dark, located in area III.

In this photo, the beach is bright and retains details, so it is located in the seventh district. The white part of the dog is also in the seventh district, and the black pattern is in the third district.

Note that the dog's left eye is slightly underexposed, but this is no problem, because if you increase the exposure for this small part, you will overexpose a large white area. This black-and-white scene is beyond the dynamic range of digital cameras, so you can't keep highlights and dark details at the same time. At this time, it is more beneficial to ensure high light.

Clouds that preserve details are usually in area VII. The sky here is brighter than the middle, so it is the sixth district.

Area exposure method and portrait photography

Landscape photographers are very familiar with the shades of natural colors, such as mountains, trees and the sky, while portrait photographers should pay more attention to and be familiar with the colors of skin and hair.

Most people's skin is between zone IV and zone VI, except some people who are very white and black. When taking portraits, you must pay attention to the skin color. The color of clothes is equally important, but not as important as skin, especially when clothes only appear in a small part of photos.

Let's talk about how to divide the skin first

In the above picture, the baby's skin is brighter, about+1.5 higher than the middle, so it is between the sixth and seventh districts. His light-colored clothes still retain the details and hardly overflow.

Maybe the dark details of his mouth have been lost, but it doesn't matter. First of all, we must ensure that the highlights are not lost. Secondly, the dark details here are not important.

The girl in this photo is darker, but still brighter than the one in the middle. Her skin color is about +0.5. The bright spot in the picture is her eyes and teeth, both of which are safe. And hair, clothes, accessories and other dark parts have not overflowed.

The man's skin color in the above picture is just the middle tone, so it is located in the V area. The dark details in this photo are lost, but the highlights are all right.

The poor old woman's skin color is-1.5 compared with the middle tone, so she is between zone VI and zone III. Obviously, her skin color is brighter than her hair, and she hasn't completely entered Zone III.

A small part of her right shoulder protrudes, but the whole is ok. If the overflow is large, this photo will be taken again. Dealing with high dynamic range scenes

If there is a big difference between the brightest part and the darkest part in a scene, it is called high dynamic range. This scene can't restore all the details in one photo. So unless you plan to use multiple photos or a medium gray filter in the future, you must give up some details. Do you want highlights or shadows more?

In most cases, the answer should be to keep the point. Never give up unless the highlight is too small to affect the picture, or the details of the shadow area are important.

Look at the picture above. Because you can't give up the white fog above, everything becomes very simple. Measure the white fog, then +2 exposure, arrange it in zone VII, and then shoot. Other parts will fall into their own areas accordingly.

The missing details in the shadow area are not a problem, because the white fog, waterline and floating boat are the focus of this photo.

In this example, the light outside the window is too bright to take care of both indoor and outdoor scenes. Here, the photographer skillfully takes the indoor characters as silhouettes, while retaining the outdoor city scenery.

In this photo, the sun appears in the picture, and it is impossible to avoid the overflow of the sun itself in any case. The only thing you can do is to leave a large shadow area and control the overexposed highlights to a small point.

So, let the sunshine overflow yourself and keep the details of other parts, such as blue sky, red flowers and green grass.

abstract

Some friends may think that the area exposure method is not suitable for digital photography, but the fact is completely applicable. Perhaps the application of digital camera is not exactly the same as that of black and white film, but the area exposure method will undoubtedly bring something different to your photography. Will force you to think about exposure and take pictures in a planned way.

The basic rule is, in the face of halftone scenes, aim at halftone objects to measure light, and then make composition shooting after determining exposure value. In the face of high dynamic range scenes, unless you plan to post-synthesize, or use fill light or medium gray filter, you must give up some details.

Do you want highlights or shadows? Make a choice for that part and expose it, and the other parts will get the appropriate position accordingly.