How to master the exposure function and know-how quickly

Lead: In order to shoot an image with a beautiful tone range, it is necessary to choose the correct exposure. This ensures that the details look neither too dark nor too. The camera allows you to simply choose the exposure, because it can measure the brightness of the scene for you and use the photosensitive unit to convert the light into an electrical signal? The more electrical signals, the brighter the image.

How to quickly master the exposure function and know how to measure light and set exposure?

For photographers, the problem is that the brightness of each part of the image may be very different. For example, under the light of summer monsoon, the sky is much brighter than the shadow area under the tree. If the exposure is set manually, the part that should be set depends on the result you want; Usually you will set the exposure for one of the two extremes. In this compromise, the method of successful exposure of the camera depends on the type of metering system it uses. Many single-lens reflex cameras offer two or brighter metering systems to choose from.

How does the camera measure light?

The exact method of exposure measurement by different cameras varies from model to model. But in fact, four types of metering systems can be found in modern cameras. Especially, the advanced performance of matrix system varies greatly, and it also depends on the camera used. On some autofocus cameras, the exposure mode and autofocus system may be combined (see 50? Page 5 1) so that the camera can calculate which part of the picture the subject is in. Then make the exposure tend to take light readings from this area.

Average measurement:

This basic system is still used in the simplest pocket camera, which reads light readings from the whole image and calculates the average value. Its main disadvantage is that it may be easily dislocated, which is most obvious when shooting backlit landscapes. The sky on the picture is obviously brighter than the foreground. The lower part of the photo is underexposed.

Central key average photometry

The working principle of this system is similar to the average photometry, but its reading often pays more attention to the brightness in the center of the picture. The theory is that the subject of the photo is likely to be in the center. Of course, not all compositions are like this, but it is easy to predict when the system will be inaccurate and remedy it accordingly.

Spot photometry

Like holding a spotlight, the system takes readings from a small area of the picture. By aiming the camera at different areas of the composition, the photographer can get many readings and calculate a representative average reading. It needs more practice, so that you can judge which part of the area is suitable for reading and know how to interpret these readings.

Matrix photometry;

This system is also called multi-area estimation photometry and can be found in many advanced cameras. It actually divides the image area into different areas, then compares the brightness value of each area, and uses its computerized memory to estimate what kind of photos to take. Then, it will compensate for components such as bright sky or dark foreground.

Manual exposure:

No matter how advanced the metering system is, the camera occasionally prompts the wrong exposure setting. Some scenes refused to follow the mathematical algorithm used by smart cameras. When is the brightness range in the photo? The difference between the darkest point and the brightest point? It is beyond the range that film or imaging chip can cope with, and it also causes some problems. No matter what exposure you set, the photo area will turn white or black. Unlike the exposure meter, the human eye can see the important things in the scene, so you can manually set the exposure to suit the focus of the composition. You can make this adjustment in many ways.

Exposure Compensation Panel: The exposure compensation panel allows you to use the built-in exposure meter to set the aperture and shutter speed, and then adjust the whole exposure value. For a single-lens reflex camera, you can increase or decrease the overall exposure by up to three levels. Experience will tell you where your built-in exposure meter will go wrong and what the appropriate correction method should be.

Avoid underexposure: Bright, reflective snow usually leads to underexposed photos. In order for the camera to take this picture? Overexposure? , using exposure compensation. The setting of 1 is a typical starting point for shooting this kind of scenery.

All white: A light background may fool most types of exposure meters. In order to take this photo, please set the exposure compensation disc at a position half a level higher than the exposure recommended by the built-in exposure meter.

Grey cardboard:

Most exposure meters assume that the black tone, bright tone and gray tone of photos are evenly distributed. But what if it's white or dark? The built-in exposure meter may try to turn these two situations into the same gray. One way to solve this problem is to use special gray board; Put it in the same position of the object and measure the reading of the reflected light.

Built-in exposure meter reading: The camera's built-in exposure meter can see the dominant white scene and set the exposure to produce an average tone range. But this means that this white water lily will become darker than the actual color.

Reading with a gray board: For this photo, the camera reads from the 18% gray board above the lily. Camera, and then there's another one? General? Scenery shooting, and produce more natural exposure.

Creative exposure:

When underexposed or overexposed, each type of film will produce different effects. Color negative is the most tolerant, even if the image is overexposed by three or more levels, or underexposed by one level, it can still produce printable photos. Color slides need to be exposed at the ideal half level, otherwise the image will obviously look overexposed or underexposed. Exposure latitude of digital sensor and black-and-white film is between color negative and slide exposure latitude. In digital or ordinary darkroom, some exposure errors can be concealed, but in order to pursue the best tone range and color, exposure needs to be appropriate and accurate. However, you can ignore this rule and deliberately gain exposure in pursuit of artistic effects? A mistake? .

Contact experiment:

Many photographers will expose color slides to less than half a level because it can produce more saturated colors. Similarly, color negative overexposed by one level can produce more natural colors and contrast. Both extreme overexposure and extreme underexposure may have artistic value. Photographers may overexpose slides as much as possible to express bright sunshine or create more abstract images. Underexposed photos, especially Gao Fancha's theme, can express an emotion, because the whole picture is dominated by black tones.

Creative underexposure: In order to take advantage of the dark background and the black clothes of the subject, this photo was conceived as an emotional portrait. Take the photometric reading of the peripheral flash from the front of the woman, and then expose the photo to below one level.

Ignore the exposure meter: Using incorrect exposure may sometimes produce interesting photos. These three photos showing the same scene were taken by slide show. The latter increased the second exposure than the former. The last photo was overexposed by 16 times (level 4), but it still provided a good abstract image.

Surround exposure:

In some cases, even if you have many years of practical experience and the best metering system, it is difficult to set the correct exposure. The consequences of unsuccessful photography are sometimes very serious, so you can't risk changing exposure. For this reason, photographers sometimes take important exposures? Surrounding method? Processing, taking a group of almost identical photos of the same subject? The exposure value of each photo is slightly different. How much exposure each time and how much exposure compensation depends on the situation and light at that time.

Surrounding exposure is particularly important when using slides, because it cannot tolerate overexposure and underexposure. Generally, a photographer can take photos based on the measured readings, and then use the exposure compensation disc to take photos with increased and decreased semi-exposure. Some cameras have the function of automatically surrounding the exposure, and automatically control the necessary adjustments to take a group of photos surrounding the exposure.

A set of photos exposed by closed method: This set of photos shows the intolerance of slides to incorrect exposure. In order to obtain accurate and high-quality results, the exposure needs to be carried out within the ideal half level. The available latitude depends not only on the type of film, but also on the contrast of the shooting scene.

Digital solution:

Some digital cameras have multiple exposure function, which allows you to compare different effects before photos are exposed. In this way, you can retake the exam until you are sure that all the components in the composition are in order. By using the digital processing software package, several different images can be synthesized in a simple way. Each layer can be modified separately, and there are many options for you to choose when making the final synthesis decision.

Three exposures: This portrait of the studio used three independent exposures. A black background means that the composition cannot be seen between different exposures.

Double exposure by combining transparencies: A simple method of double exposure is to put two slides in the same frame. When landscape or portrait sketches are combined together, patterns will play a very good role.

Projection image: One way to superimpose one image on another without using double exposure mask or other camera technology is to use two independent projectors to project two slides on the same screen. By adjusting the position of each projection, you can process image components.

Exposure compensation: If light components are combined in the overlapping part of double exposure, there is a danger of overexposure of the final image. Here, the solution is to expose these two images by less than one layer. This can be achieved by setting the film speed on the camera to twice the film speed used.