The formula of sixteen-sunshine method:

Sixteen sunny days and eight cloudy days

Cloudy, eleven days and four nights.

Cloud cover exceeds 5.6.

Rain, snow and sunset.

Indoor court for two seconds

Shutters on the living room stage 8

first step

Set the shutter to the number of sensitivity, for example, ISO 50 sets the shutter to 1/60, and ISO 65438 sets the shutter to1125. In short, let the shutter speed be as close to the sensitivity as possible.

Second step

If the weather is clear, set the aperture to f 16.

If it is slightly cloudy, the aperture is set to f 1 1.

If it is cloudy, set the aperture to f8.

If the weather is very gloomy, please set the aperture to f5.6

How to distinguish the degree of cloudy sky?

Just observe the shadow. If the shadow is clear but the edge is a little blurred, it is slightly cloudy. If the shadow is unclear but still visible, it belongs to the sky. If there is no shadow, it is very gloomy.

You can also use the sunshine rule of 16 to verify whether the metering of your camera is accurate, especially when buying a camera.

The built-in exposure meter in the camera measures light through the lens (TTL:through-the-lens), which greatly simplifies our photography work. In fact, we rely on this kind of exposure meter. Without it, when all kinds of things appear in front of our lens, we will be a little lost or confused. I know that some photographers can accurately estimate the correct exposure parameters by experience. They are proud of their ability, but I am not such a person.

However, in one case, the correct exposure parameter is a constant, that is, when you take pictures in bright sunlight. In this case, in order to get the correct exposure value, you should follow some rules that we call "sunny f/ 16": in bright sunshine (no clouds, no fog, no air pollution), from a few hours after sunrise to a few hours before sunset, the correct exposure value of the subject with positive illumination is close to that of exposure value, which uses negative ISO as the shutter speed and sets the aperture at the same time. Hehe, that's a bit too empty. Let's study these rules more deeply.

First of all, "Sunny f/ 16" is only suitable for direct sunlight, not for direct sunlight in the early morning or dawn, nor for foggy or cloudy lighting. Moreover, this rule is not suitable for deep winter in North America, because the sun at this time is very close to the horizon and the light is very low. "Sunny f/ 16" is also not suitable for macro, because the effective aperture size of many lenses will change when focusing at close range. Theoretically, the value of the aperture f is accurate only at infinity. Under the same aperture, the closer the focus is, the less light will enter the lens at the focus. But usually don't worry about this problem, because your TTL exposure meter has taken this change into account. But the rule of "sunny f/ 16" is the exposure value when the exposure meter is not used, so when these conditions change, this rule will not work. And this rule only applies to subjects in positive light (the sun shines directly on the subjects from a height above your shoulders). Therefore, at noon in summer, when the sun is shining directly from overhead, only when you want to pat your feet from top to bottom can you apply the "sunny f/ 16" rule. If you want to shoot as usual at this time, you need to modify the parameters of the "sunny f/ 16" rule to meet the exposure requirements of sidelights. I will briefly introduce how to modify it later.

Also, this rule is only valid for subjects with ordinary tones, and objects that are too bright or too dark will have problems. In fact, the colors of most subjects are very uniform, and in the words of photographers, they are all "middle tones". Personally, I don't like the word "middle" very much, because too many photographers use the word "middle tone gray" when discussing tones, but we are not talking about black and white photography. So I use the word "medium" instead. In this way, we can say "medium green", "medium red", "medium blue" and so on. (Translation: these words: average, alto and average really confuse me, and I don't know how to translate them properly. In fact, what they want to express is the concept of 18% ash. )

Don't forget that when using the "sunny f/ 16" rule, it is not necessary to use the ISO value as the shutter speed and f/ 16, and other equivalent exposure parameters can also be used for exposure. And there is no mention of the place of use in this law. Someone once asked me if I could use the "sunny f/ 16" rule at the top of the mountain. The answer is yes, because the sun is 93 million miles away. I don't think that when we approach the sun at 10000 feet and 12000 feet, it will have much influence on the "clear f/ 16" rule.

Let's assume that ISO 100 film is used, and the "sunny f/ 16" rule is used. Under normal circumstances, the exposure parameters are1125 seconds and f/ 16 or other equivalent values. In bright sunshine,1125 seconds and f/ 16 are not necessarily used, but 1/250 seconds f/ 1 1/500 seconds f can also be used. If the shutter speed is slow, you can shoot with1/60seconds f/22 or1/30seconds f/32. These exposure parameters can allow the same amount of light to reach the negative. If ISO400 film is used, it should start with 1/400 seconds f/ 16, if ISO25 film is used, it will start with 1/25 seconds f 16, and so on.

The same exposure means that the same amount of light shines on the substrate, so different exposure parameters can be used to achieve the same exposure according to the needs of the shooting environment. Do you need a high-speed shutter to capture instantaneous motion? Or do you need a small aperture to achieve a greater depth of field? If you shoot a running deer with ISO50 film, will you still use the parameter 1/50 seconds f/ 16? Please think it over before you say "no" without thinking. In that case, is there really only one correct exposure combination? Don't you like to express the feeling of sports with fuzzy pictures? In any case, the correct combination of aperture and shutter depends on what kind of photos you want to take. Whether the exposure is correct or not depends entirely on you.

In most cases, when shooting wild animals, you will use your longest lens, and more often, you will adjust the appropriate shutter speed to capture the instantaneous picture. However, starting from f/ 16, it is time-consuming to calculate how big the aperture is to match the shutter speed, but there is a simpler method. It is equivalent to the law of "clear f/ 16". You can use what I call "fast f/5.6" to achieve the same exposure as "clear f/ 16": add a zero after the ISO value of the negative you use as the shutter speed, and use f/5.6 as the aperture. For example, ISO 100 negative film, "Clear f/ 16",125 seconds f 16, "Fast f/5.6" and1/KLOC-0. Are they the same? Through conversion, you will find that their exposure is the same. When shooting animals, this method is very convenient to use, because it can save a lot of calculation, and usually the aperture you use at this time is also near f/5.6.

By the way, I don't know if you still remember it. This estimate is that exposure value is aimed at the subject with positive light. For objects with side lighting, it should be one step larger than the basic exposure value; For an object with backlight (backlight), you should turn it up two notches; For objects with lighter colors in the whole picture composition, one block should be reduced; For dark colors, turn on the big gear. However, please remember that these estimated exposure value are only used without exposure meter, and they are not applicable when TTL exposure meter is used.

Here is an experiment: How to estimate the correct exposure value when shooting a close-up of egrets in Florida sidelight on a sunny day? You should be able to estimate the correct result. Because we will use telephoto lenses, we use the "fast f/5.6" rule. Reduce one exposure and record the white details of the egret. Because of the sidelight, we will open a new space and return to "Fast f/5.6" exposure value, which is our estimated exposure value. Let's try shooting dark brown bison in Yellowstone National Park on a sunny day in September. The bison we photographed didn't move much, so we used the rule of "sunny day f/ 16". Because it is a dark object, it opened a large piece; Because it's backlit, I'll drive two more gears. This * * * opens the third exposure value (from f/ 16 to f/5.6). Of course, you can also choose an exposure parameter that you think is appropriate by increasing or decreasing the aperture or shutter combination.

Although you don't always use these estimated exposure parameters to take pictures, the rule of "sunny f/ 16" is a very helpful reference. You can use this rule to check your exposure meter reading at any time, because this rule provides a known exposure benchmark. If you shoot in bright sunlight, your exposure meter reading should be similar to the "sunny f/ 16" rule, unless something goes wrong. Is the battery of the camera dying? Or did you forget to unscrew the filter from the lens (for example, using a polarizer usually requires two exposures)? When shooting in bright light conditions, such as shooting birds in Florida or shooting wild animals in Kenya, it is best to set the exposure parameters of the camera to an estimated value in advance to cope with some unexpected situations and facilitate snapshot.

There is another problem in using the "sunny f/ 16" rule. You need to know how to set the aperture of the lens to f/ 16. This seems to be a simple question, but it is not easy for some shots. Nowadays, many zoom lenses adopt a design called "variable aperture". When the lens zooms, the actual aperture size will also change. These lenses are marked with two F values, such as Nikon 28- 105mm f/3.5-4.5 or Canon 35-350mm f/3.5-5.6. If we want to achieve a constant aperture, when the focal length of the lens changes, the aperture must also change accordingly. If the physical size of the aperture remains the same, the F value of the aperture will change when the lens is zoomed. For most variable aperture lenses, the aperture value marked on the lens is correct only at the short focal end. For old cameras, either the "sunny f/ 16" rule is used only at the short focal end of the lens, or the appropriate aperture value is guessed with the zoom of the lens. I call some cameras "old-fashioned" because many new models of cameras can set the aperture value electronically or have this optional function. All Canon lenses work like this. Nikon lens can be set mechanically through the aperture ring on the lens, or electronically by using the indicator dial on the camera body. When set electronically, the aperture value you set is the actual aperture size, except for the maximum and minimum apertures at the telephoto end.

We use Nikon 28- 105mm lens to illustrate the phenomenon mentioned above. When the aperture is opened to the maximum, the focal length of the lens is zoomed from 28mm to 105mm, and the aperture size is also changed from f/3.5 to f/4.5. There are two-thirds flights here. This 2/3 gear change will also occur at the minimum aperture. At the end of 28mm, the minimum aperture is f/22; 105mm ends with f/29. If the aperture value is set between f/4.5 and f/22 electronically, the aperture will remain unchanged when the focal length of the lens changes. Based on the above facts, if the "sunny f/ 16" rule is used when using electronic cameras and zoom lenses, the maximum or minimum aperture should be avoided. As long as the intermediate aperture value is used, it will not have any influence on the application of the "sunny f/ 16" rule.

By the way, if you never knew that there was such a thing as estimated exposure and the "sunny f/ 16" rule before, you really missed a very useful tool. If you want more information, please check the contents printed in the Fuji or Kodak film box.