Basic theory of exposure
Do not have questions, whether professional photographers or amateurs, all photographers have to face the main problem that the film is exposed correctly. If the exposure is wrong, the other is a joke. You may have the latest most expensive equipment, go to those most charming places, to reach the most appropriate position in the most appropriate time and light, and your photography technology is very exquisite ... But the wrong exposure will be Let you take a bunch of photos that can be thrown directly into the trash can.
For many photographers, the exposure value exposure recommended in the built-in test in their cameras is the correct exposure. However, can the metering table tell us about the correct exposure value? I will discuss this topic in depth, if you want to become a better photographer, the in-depth understanding of the exposure theory is a good start, because exposure is the most basic in the concept of photography. If you want to avoid the basics of these photography, it is impossible to successfully face more advanced photography technology.
I assume that your photo quality is very important to you, otherwise you must continue to read. If you intend to shoot a good photo, you will be able to control the entire process of exposure. "Control" can be implemented in this way, using all the exposure parameters on the camera, then select one of the best, but this is obviously a waste of film and time. If you plan to do this, don't you, how do you record only once a life? Your goal should be ready to expose correctly in all possible situations, and know that your exposure is what you want. This is of course not to say that we must always set the exposure parameters, and ignore the camera's metering table, but I personally believe that the camera's manual mode is the most easy to use, because you set it is that you finally get. Use "Aperture Priority" or "Shutter Priority" to take a wonderful photo, but the premise is that you have to know how the camera selects exposure parameters, and there is enough knowledge to make you correctly measure the settings of your camera. Not what you want, you must know how to modify them when you need it. As a photographer, your camera should always be controlled in your control, but don't let your camera control you.
Before I start discussing how to expose correctly, we need to define terms that are often misuse or misunderstandings. "Correct exposure" means that the exposure of the film is carried out in the exposure result you want. For example, for example, you take a photo of a sandstone and blue sky in Arches National Park. If you want the sky on the backware, it is really light blue after it is actually washed out. Then your exposure is "correct exposure." Because you get the results you want.
However, what if the sky on the film is not light blue? That means you set a wrong exposure value. If the tone of the sky is more shallow than you want, then your negative "exposure is over". In this case, the light blue sky becomes gray, or it is a white blue blue, which is a lot of light blue than you shoot.
Of course, there will be a problem with the opposite mistake, the tone of the sky is deep than you want. For example, on your negative, light blue sky becomes blue or dark blue. At this time, you get a negative film that is insufficient. However, if your photo topic needs to express this dark tones, your exposure is also the correct exposure.
Simply, "correct exposure" refers to the negative film exposure results and the consistency you want; "exposure" means the performance of the negative exposure than you want; "Insufficient exposure" refers to the darkness of the exposure than you want. Note that in these three situations, there is no mention of the metering table in the camera. The exposure is correct or no relationship between the reading of the meter in the automatic exposure system. The exposure value of the metering meter is just a reading at a particular exposure level, which may be the correct exposure setting, perhaps not. If you have been using the camera metering watch (for example, set your camera to Auto Exposure "mode), you may get the exposure result of hope, sometimes it is not. The problem is: Is these exposure results What do you want? Why is it wrong? A solution is to use a negative piece (negative piece has a certain advantage in solving the exposure problem) and corrects the exposure problem when zooming in. However, let exposure problems have always existed not a realistic solution. As the saying goes, "garbage is the garbage", the best way is to correct it before the error occurs. I have read an article about randomly ask the passerby in the street. What is the definition of your comparison? "The result is that many people definpected to" photo quality "can recognize themselves from the photos. They don't care if there is any loss, the composition is not good enough, and it is not true that the color is restored. Of course, I believe this definition must not be accepted by you. If you are almost the age and my age, then you must also remember the color TV. At that time, I can't wait to go to the neighbor's watch to watch TV, because his home is the first to buy color TV in the neighborhood. At that time, the color TV has a very exaggerated and even horrible color performance, but when the ED Sullivan's orange color face appears on the screen, is it so much? At least he is colored, this is enough.
Thank God, we have passed the age, and now the performance of color TV is very close. This example also tells us that not only the development of color TV is going to experience this process, and our photos will also have this process. Ability to make us wonderful photos, not a shot or a model of film, nor a rare very mysterious filter. It is possible to make us a wonderful photo, which is the proper use of photography technology, which includes in-depth understanding and application of exposure process. Our ultimate goal is to achieve, no matter what light conditions, we can expose the film correctly in any place. Compared with the luck, the negative exposure is correct, we need to master exact and skilled photography techniques and techniques that can be applied at any time.
In my opinion, the control of exposure is the most important component throughout the photography process. You must learn to make sure that the imaging on the negatives is the same before pressing the shutter. Of course, this is a gradual learning process. For an initiator, a very good photo is placed in an eye, perhaps belonging to the scope of being abandoned. But don't be discouraged, your ability to control the film will gradually increase with your efforts. Our ultimate goal is not a slave, which is a prosthetic exposure rule, but is able to grow into a real photographer based on fully understanding the theory and technology.
Now I will continue to explain some important nouns so that we can use text to discuss the exposure problem. During the entire photography process, things related to exposure will focus on an important concept "block". "Block" is defined here as half of a given parameter or twice. They are associated, for example, for a given exposure parameter, you may need half of this parameter, or double the parameters. This half and double concept will often appear in the discussion of the exposure. The clearer the understanding and use of the "gear", the more you can use to expose the exposure control.
Three factors in any photographing process determine how much the actual exposure: (1) The shutter speed set by the camera machine; (2) The aperture size of the lens; (3) The sensitivity of the film used. "Shutter Speed" determines the length of time to open the shutter curtain, which determines how many light can be irradiated on the film. The value of the shutter speed indicates the interval of the shutter to close, usually in seconds. "Aperture" determines the size of the lens open, when the shutter is opened, the aperture size determines how many light can be irradiated on the film by the lens. This setting is usually represented by the value of "F-gear". "The film sensitivity" indicates the rate of chemically reacting the photosensitive material on the backsheet in a certain light irradiation, typically expressed in an ISO value. All of the above three parameters are set by double or halving half of the "gear" bit, and the three parameters are associated with each other. Let's introduce these three parameters first, then explain the relationship between them. Shutter speed
The shutter speed expresses the length of time by second or insect second. Different camera manufacturers have different shutter speed starting ranges, which is also very important. All single-lens reflex cameras have at least the following shutter speed (maybe more): 1, 1/2, 1/4, 1/80, 1/1/1/30, 1/60, 1/125, 1/250, 1/500, and 1/1000 seconds. Some cameras use a simple way, such as labeled 1/30 seconds as "30". For distinguish seconds and seconds, different colors or their special tags are generally used in the fuselage. For example, Nikon and Canon's fuselage denoted second seconds rather than 1/2 by adding a semicolon (") tag after digital 2. Read your camera carefully to see how your camera is distinguished.
Looking at a series of shutter speeds will find that every shutter speed is half the previous speed, but a double. For example, 1/25 seconds is half of 1/60 seconds, but doubled by 1/250 seconds. They all differ a "gear", each gear is half or double the time. Moved from 1/125 seconds to 1/250 seconds (time halving), to 1/500 seconds, move a gear (half again), moved to three stops from 1/1000 seconds. Waiting for a small exam: How many gears are required from 1/30 seconds to 1/500 seconds? Reverse the opposite direction (slow shutter direction to the speed), from 1/30 seconds to 1/2 seconds to move a few blocks? Do you know the correct answer? The answer is simple: you need to move 4 gears.
Most cameras can implement "stepless" shutter speed when the camera is set to a particular automatic exposure mode. That is, the shutter speed can be determined by the electronic device and set to any shutter speed without being limited by the fixed gear. But even if the camera is set to this mode, "halving" and "double" concept still exists. In the new listing camera in recent years, the shutter speed of most cameras can be reduced by 1/3 gear. For example, the shutter gear of my Nikon camera includes: 1/8, 1/10, 1/13, 1/1/1/25, 1/30, 1/40, 1/50, and 1 / 60 seconds, etc. From 1/30 to 1/60 seconds, it is the same, from 1/20 to 1/40 and from 1/13 to 1/25.
When you change the shutter speed, it also changed the way the motion physics is recorded on the film. The faster the shutter speed, the movie object will show a clearest image in the film, but in turn, the slower the shutter speed, the more blurred the moving object.
aperture
The lens is in size, the same gear is used, and the value of the F gear is used. However, it is worth noting that although the F-gear is also halved or doubled between each stop, the value of the F stop is not halved or doubled. Standard F stops are: f / 1, f / 1.4, f / 2, f / 2.8, f / 4, f / 5.6, f / 8, f / 11, f / 16, f / 22, and f / 32. Not all the lenses have these gear, generally only some of them, especially those who use large negatives (more than 35mm), there may be some other gear. The most important point is that these values should be understood that the aperture of the aperture passing through the lens is the size of the aperture (aperture). The above aperture value sequence includes all gear. Each gear relative to the gear before and after it can only make half or double light through the lens. Be sure to record the values of these aperture gear and can be easily increased and decrease. Although the aperture value does not write a score from a value, it is actually a score. The difference between the aperture value is also convenient to understand the relationship between the aperture value and the aperture size: the larger the aperture value, the smaller the aperture, and the less light through the lens. For example, F / 2 represents a relatively large aperture aperture and can pass a lot of light, and F / 22 is a small aperture aperture, only a little ray can pass. You can understand them to understand: 1/2 is much larger than 1/22.
Today, many cameras can display aperture value in a digital manner, and can achieve 1/3 gear in a shutter speed. For example, you may find these F values: 4, 4.5, 5, 5.6, 6.3, 7.1, 8, 9, 10, and 11. As long as you remember that the change is changed, there must be a change in increment, and no matter which one starts. From F / 4 to F / 5.6, it is the same as a gear from F / 11 to F8. Similarly, from F / 5 (1/3 of F / 5.6) to F / 7.1 (1/3 of the F / 8) or from F / 6.3 to F / 4.5. Although they are not linear, they also apply halved and doubled concepts. It is also necessary to mention that some cameras can perform 1/2 gear reduction settings, and some (for example, Nikon F100) can set all gear by program control: 1/2 block or 1 / 3 block. Remind, you must take a closer look at your camera manual.
In modern lenses, only some of some fewer aperture ring is reserved. Nikon's lens has always had this function (including the lens of all big frame cameras). Although the aperture ring is typically a significant pause in the position of each gear, it is still possible to turn the aperture to any one. The sensation of the aperture loop is only convenient to calculate a few gears, and there is no other meaning. Most large post-frame cameras have a pointer or scale to indicate aperture value.
Two terms have been used to represent changes in the aperture. "Open" means that the aperture is larger and makes the lens a larger passto diameter. This means that more light is irradiated on the film through the lens. Another term "contraction" achieves the opposite process, making the aperture, reducing the number of lights reaching the film through the lens. So it can be said: Open a large aperture from F / 8 to F / 4, or shrink from the F / 8 to F / 16.
The shutter speed and the aperture size can be controlled to control how many light can reach the film, and these two factors must be considered simultaneously. They are all working in a gear, and they are related to each other, we call it "mutual relationship." Once you can determine the total amount of light, the total amount of light, the shutter speed, and the aperture size, can be quickly determined according to the mutual relationship to determine the value of the other should be set. In the case where the total amount of light irradiation is not changed, the change in the speed of a shutter speed is equivalent to a change in the inverted direction. That is to say, one of the shutters and the aperture is half, and the other is doubled, and the total amount of light (that is, exposure) is the same through the lens.
Mutual relationship is a very important concept, so you have to understand it. You can understand this way, double the shutter speed and halve the amount of light through the aperture, and completely equivalent to halving the shutter speed to simultaneously open the large radio to enter the lens. Let's do two metaphor, for example, you want to fall a liter, you can open the faucet, you will be full in a moment, you can also open the faucet, let the water drift down, so It takes a long time. But these two methods don't have any difference, and you can eventually get one liter. This is a mutual relationship. Let's make an example, you need to earn 20 yuan. You can find a hour you can earn 4 dollars, do 5 hours; or find a job every hour of earning 5 yuan, dry 4 hours. Or otherwise, 2 hours per hour, or 10 hours per hour. You can choose anything, but in the end you get 20 yuan. Expressed by the term photography, that is, it can use a slow shutter to add a small light or with a fast shutter to increase the aperture, and the amount of exposure obtained by the two methods is the same. However, (note, this is important) The effect of two methods imaging on the film is different. Different imaging effects I will introduce in the chapter behind the depth of field and moving objects. From this point, as a photographer, you should start learning how to judge your photo is consistent with the effect you want.
In actual operation, the mutual relationship means that once a specific exposure is obtained, once you get a specific exposure, you can choose a shutter and aperture combination after getting a specific exposure. Correct exposure. It is assumed that the appropriate exposure value for a scene is 1/15 seconds and f / 11. You can increase the shutter speed to 1/8 seconds (change a gear, the shutter time is doubled) and shrink the aperture to F / 16 (also changed a gear, the light is reduced). Because 1/15 seconds and f / 11, it is completely equivalent to 1/8 seconds and f / 16. Similarly, 1/4 seconds and f / 22, 1/30 seconds and f / 8, 1/2 seconds and f / 32, and 1/60 seconds and f / 5.6 can also be used. All of these combinations allow light of the same total light to the film and get the correct exposure. Understand these, we can choose to use the aperture size or shutter speed we need, and make adjustments in compliance with the relationship.
In fact, this mutual relationship is easier to implement on the camera than we discussed here. When you change the setting of the aperture or shutter, the changed gear is recorded, and the other setting of the same gear is also changed. As long as the one is increased, the other is reduced, and the same exposure can be guaranteed. For example, assuming 1/250 seconds and f / 4 are correct exposure values. Then add 4 blocks to 1/15 seconds (increasing the shutter time), while you need to shrink the 4-shovel to F / 16 (reduced the aperture) so that the same exposure can be obtained. If your camera's shutter and aperture have the same increment, such as 1/2 block or 1/3 block, you can use the shutter turntable and the aperture ring.
Backsheet speed (sensitivity)
In fact, the shutter speed and the choice of the aperture depends largely to see the type type used in your shooting. The film is represented by the sensitivity of the light using "negative", or is called an ISO value. The negative ISO value is referred to as a "slow" film, since more light is required to complete the chemical reaction on the film during the negative image on the film; in contrast, the negative "fast" negative film is called "fast" negatives because they need The less light can complete the same thing. We usually classify the negative of the ISO value of less than 100 as a slow film, the ISO value is 100-200, called a medium-speed negative film, and those ISO values are greater than or equal to 400, called a high-speed negative film. Later I will have a special section to discuss the negatives in more detail, but it will now be explained now, that is, with the increase in the film, the image quality of the film will decline.
I have previously mentioned that the speed of the film is also expressed in the way "block" position, and the concept of Double and halving is also used, just like the shutter and the aperture. Rethony, your more thorough understanding of the concept of "blocking", the easier you will be more and more about the in-depth understanding of exposure. The expression of the film is a line-shaped sequence, and each ISO value represents a gear, and each block is doubled or halved. For example, from ISO50 to ISO100, it is different from ISO 50, and the ISO 200 is the second gear, and then the ISO400 is different from three gears. These values are easily calculated by simple double or halving. Another example is, for example, between ISO1600 and ISO25 a few gears? Yes, maybe you see, I tried to confuse you through the counterconstruction, but if you understand this calculation, you will not be confused and calculated the correct results. So, starting from 1600, we can calculate 800, 400, 200, 100, 50, 25, a total of 6 blocks. The understanding of the relationship between the ISO value is very helpful to you choose the right film when you are properly. If you already know the amount of exposure required to use a speed of the film, you can easily convert the exposure of the same exposure using another speed, the premise you know these two The speed relationship of the film. In fact, it is very simple, but it is only possible to increase or decrease the gear. For example, if it is a Kodak E100S (ISO100) film, the correct exposure parameter is 1/15 seconds and f / 8, and if the correct exposure parameter should be used when using Fuji ProvIA 400 (ISO400) negatives? Calculate the different ISO value: starting from 100, double the 200, doubleding 400, so the ISO value adds two gears. Therefore, the exposure parameters of the E100S are changed to the correct exposure parameters of the Fuji negative. We change the exposure parameters to: 1/60 seconds and f / 8. Of course, you can change to any equivalent exposure value, such as 1/60 second f / 8 equivalent to 1/125 second f / 5.6 or 1/250 second f / 4 or 1/500 second f / 2.8, or change one direction 1/30 seconds f / 11 or 1/15 seconds f / 16 or 1/8 second f / 22.
The standard negative slime speed gear is also incrementally increed in 1/3.
25 32 40 50 64 80 100 125 160 200 250 320 400 500 640 800
Not all speeds have corresponding negatives, but it is necessary to remember that the ISO value is doubled or halved means that the difference is one stop. ISO 200 is slower than ISO800, but it is twilight than ISO50. From the above sequence, Kodakchrome 64 (ISO64) can be obtained from Porvia 100F (ISO100).
Some cameras can't display all ISO values on the fuselage because there is no place to mark as many numbers. Therefore, the 1/3 gear increment on these cameras is expressed in a dot, similar to the following:
"..........................
In addition, on the camera, the shutter speed or the aperture F is also identified by this dot, as they may not have a large carousel, not enough to mark these numbers.
A gentle increment indicates that the concept of double or halving is a basic principle in photography. It should be studied to think of the exposure problem with the concept of this gear. My photographer's work, as well as the discussion of this book, is based on the understanding of the concept of the gear. If you are not adapted to these concepts, please read patiently. The understanding of exposure basic theories and gear concepts are destined to have a lot of help to your photography and you want to be a better photographer.
Exposure when there is no metering table: "Sunny F / 16" rule
The metering metering of the TTL: Through-the-lens in the camera simplifies a lot of photographs in the camera. In fact, we do this very dependent on this metering table. If there is no it, when all things appear in front of our lens, we will feel some lost or confusing. I know that some photographers can estimate the correct exposure parameters with experience in experience, they are also proud of their ability, but I am not such a person. However, in one case, the correct exposure parameter is a constant constant, that is when you take photography in the bright sun. In this case, in order to get the correct exposure value, you should follow some of our rules we call "Qingtian F / 16" rules: under bright sunlight (high altitude is cloudless, no mist, no air pollution), It is approximately a few hours from the sunrise until a few hours before the sun, approximately close to the correct exposure value of the front light, is approximately close to the shutter speed with the negative ISO, and the aperture is set to f / 16. The amount of exposure, or any other equivalent exposure parameters. Oh, this is a bit too empty, let us learn more about these rules.
First, "Sunny Tian F / 16" is only suitable for bright, direct sunlight, not suitable for solar light in the early morning or dawn, is not suitable for misty or cloudy light. And this law is not suitable for use in a deep winter in North America, because the sun is very close to the horizon, the light is very low. "Sunny Tian F / 16" is also not suitable for tiny, because many lenses change the size of the aperture when the near-distance focus is changed. In theory, the aperture F value is only accurate in the unlimited far, and when the focus is proximally, the light of the lens will be reduced. But usually don't have to worry about this problem, because your TTL metering table has calculated this change in. However, "Sunny F / 16" rule is the exposure value when metering, so when these conditions change, this law is not good. Moreover, this method is only suitable for the subject applied to the front light (sunlight is directly illuminated from the height of your shoulder to the subject). So, in the noon in the summer, the sun is straight from the top of the head. Only when you want to shoot your feet from the top, you can apply "sunny day F / 16" rules. If you want to shoot often, you need to modify the parameters of the "sunny day F / 16" rule to adapt to the exposure of the side light, and later I will make a short introduction how to fix it.
Also, this rule is only valid for the subject of average (Average) tone, too bright or too dark objects. In fact, most subjects of the subject are very uniform, saying that the photographer says, is "MiddleToney). I personally like "middle" this statement, because when we discuss the hue, there are too many photographers using the words "Middle Gray", but we are not discussing black and white photography. So I use "Medium). This will be said to be "medium green", "medium red", "medium blue", etc. (Translation: These words: average, middletone, Medium really put the misty water, I don't know how to turn it is appropriate, in fact, it should be 18% ash concept)
Don't forget, when using "sunny day F / 16" rules, don't be used as shutter speeds and f / 16, but also use other equivalent exposure parameters. And this rule did not mention the location of the use. I have been asked if I can use the "sunny day F / 16" rule. The answer is sure, because the sun is from us 93,000,000 miles away, I don't think there is how much impact on the "sunny f / 16" law when we approach the sun 10,000 and 12,000 feet.
Now let us assume that ISO100's negatives, use "sunny f / 16" rules, the exposure parameters under normal conditions are 1/125 seconds and f / 16 or other equivalent values. In the bright sun, there is no need to use only 1/125 seconds and f / 16, you can also use 1/250 seconds f / 11, 1/500 seconds f / 8, 1/1000 second f / 5.6 or 1/2000 seconds f / 4. Using a slow shutter speed, you can use 1/60 second f / 22 or 1/30 seconds F / 32 to shoot. These exposure parameters can allow the same number of light to reach the film. If you use ISO400's negatives, then start from 1/400 seconds f / 16, if you use ISO25 negatives, it is 1/25 seconds F16, ... and more. The same exposure means that the same number of light is irradiated on the film, so the same exposure can be achieved using different exposure parameters according to the need to be used according to the need for the shooting environment. Do you need to use high-speed shutters to capture instantaneous actions? Or need a small aperture to achieve a relatively large depth of field? If you are shooting a running deer with the ISO50, will you use 1/50 seconds f / 16 parameters? Before you say "no", please think carefully. Is there only one exposure combination in that case? Don't you like the feeling of motion with a blurred picture? In any case, the correctness or not of the aperture and shutter combination is determined what kind of photos you want to take. Whether the exposure is completely determined by yourself.
In most cases, when you shoot wild animals, you will use your longest shots, and more time to adjust the right shutter speed to capture the moment. However, from F / 16, the calculation of the aperture should open a few gears to match the shutter speed is suitable for a time, but there is a simpler way. It is equivalent to "sunny f / 16" rules, you can use the "fast f / 5.6" rule to achieve the same exposure as "sunny f / 16": add a zero after adding the ISO value of the negatives you use. As the shutter speed, the aperture is used to use F / 5.6. For example, use ISO100's negatives, "sunny days F / 16" use 1/125 seconds F16, "Fast F / 5.6" uses 1/1000 seconds f / 5.6. Are they the same? By converting, they will find the same exposure. When shooting animals, this method is very convenient because you can calculate a lot, and usually at this time you use the aperture near F / 5.6.
By the way, I don't know if you still remember that this estimated exposure value is a subject for the front light. For objects of the side light, it should be larger than the basic exposure value; for the object (reverse light) of the back, it should be opened; for the entire picture composition, the color is very shallow object, should be reduced; The color is very deep. However, remember that these estimated exposure values are only used without metering tables, they do not apply to the use of TTL metering tables.
Let's take an experiment: sunny day in Florida, shoot the big close-up of the Egret in the side of the side, how should I estimate the correct exposure value? You should be able to estimate the correct results. Because we will use a telephoto lens, use "Fast F / 5.6" rules. Reduce a gesture to record the details of the white egret, because the side light is slow, now returns to the exposure value of "Fast F / 5.6", which is the exposure value of our estimation. Now let's try again in the sunny day in September, to the Huangshi Park backlight dark brown bison. The bison we took was not moving, so we used "Sunny Tian F / 16" rules. Because it is a dark object, it will open a big stop; because it is backlight, it will open the big two. Such a total of three gear exposure values (opened from F / 16 to F / 5.6). Of course, you can also open a large or narrowing a combination of aperture or shutter to select a exposure parameter you think.
Although you don't always use these estimated exposure parameters to take photos, "Sunny F / 16" rules is a very helpful reference. You can often use this rule to check the reading of your metering table, because this rule provides a known exposure benchmark. If you shoot under the bright sun, your metering table should be similar to the "sunny day F / 16" rule, unless there is something wrong. Is it not a camera battery? Or you forgot to screw the filter from the lens (for example, using a polarizer generally need to open a big two-stop exposure)? When shooting under bright illumination, such as patted birds in Florida or in Kenya wild animals, it is best to pre-set the camera's exposure parameters as an estimate, so that some burst things can be paid to capture. If you use "sunny f / 16", you will also encounter a problem, you need to know how to set the aperture of the lens to F / 16. This seems a simple question, but it is not easy for some lenses. Many of the zoom lenses today use a design called "variable aperture", when the lens zoom, the actual aperture size is also changed. These lenses use two F values to their maximum aperture values, such as Nikon 28-105mm F / 3.5-4.5 or CANON 35-350mm F / 3.5-5.6. If a constant aperture is to be achieved, the aperture must also be changed accordingly when the focal length of the lens is changed. If the aperture keeps the physical size constant, when the lens is zoomed, the aperture f value changes. For most of the lens of the variable aperture, the aperture value labeled on the lens is only correct at one end of the short focus. For old-fashioned cameras, or only the "sunny f / 16" rule with only the lens short focus, or the appropriate aperture value is speculated as the lens zoom is specifically. I said that some cameras are "old-fashioned" because many new types of cameras can set a aperture value by electronic control, or this optional function. All CANON lenses work in this way, the Nikon lens can be used either through the aperture loop on the lens, or the instruction turntable on the camera can be electronically disposed. When using an electronic configuration, the aperture value you set is the actual aperture size, and only the maximum and minimum aperture of the long coke is an exception.
Let us use the Nikon 28-105mm lens to explain the phenomenon above. When the aperture is driven by maximum, the lens focal length is zoomed to 105 mm, and the aperture size will also be changed from F / 3.5 to F / 4.5. There are 2/3 gear changes here. This 2/3 gear change will also occur in the minimum aperture. At 28mm end, the minimum aperture is F / 22; at 105 mm end, it is F / 29. If an electron mode is used to set a aperture value between F / 4.5 and F / 22, the aperture remains constant when the focal length of the lens changes. Comprehensively, if you use "sunny f / 16" rules when using electronic cameras and zoom lenses, you should avoid using the largest or minimum aperture. As long as the middle aperture value is used, there is no impact on the application of "sunny f / 16" rules.
By the way, if I have never known that it is estimated to expose and "sunny day f / 16", you really missed a very useful tool. If you want more information, please see the contents of the printed in Fuji or Kodak Coil box.
Depth and shutter speed
All wild photography will have some cases that need to be folded. The aperture and shutter combination you used during shooting must decide on a lot of practical conditions: Are you shooting still scenes or run animals? Does the subject have sway because of the wind blow? How long do you use the lens or how much is the magnification? Do you want your photo to eventually imagine how sharp or how much? No suitable answer can solve all the problems above, and you must choose the right step according to your final expectations.
The first decision that should be made is that you should choose what kind of shutter and aperture combination. You need to shoot sports (using fast shutters and big aperture) still need to use large depth shots (by using small aura and slow door implementation)? "Depth of field" refers to a clear area near the focus of the photo. In theory, only one plane is in the best focus position: the plane where the lens focus is located. But in fact, clear and sharp imaging can still be obtained in a certain range before the focus plane. When exceeding this relatively sharp range, whether the sharp level of imaging will fall, both in the focus plane.
This imaging sharp area is also the actual size of the "depth of field" to determine from four factors:
1. The actual aperture size when shooting
2. The focal length of the lens used is short
3. The size of the subject
4. Distance between the camera and the subject
Let's take a look at how these four factors affect the depth of view. For all lenses, the depth of field increases when shrinking the aperture. On the contrary, when the large radio is opened, the depth of field will decrease. On the same lens, the aperture is set to F / 16, F / 22 and F / 32 relative to F / 2, F / 2.8, and F / 4, can achieve the largest depth of field. The smaller the pore size of the aperture, the greater the depth of field; the larger the aperture pore size, the smaller the depth of field.
If you repeat the same object in the same place, no matter which given aperture F, when the focal length of the lens is increased, the depth of field will decrease, and vice versa. For example, if you replace a 28mm wide-angle lens to 200mm medlar lens, even if the same F value as wide-angle lens is used on the median lens, there will be a small depth of field than wide-angle lenses. At the same time of replace the lens, the size of the subject is also changed in the photo. Since there is no change in the shooting position, the perspective effect of the photo has not changed, but because the slider is used, a larger subject can be seen in the viewfinder. Now passing the viewfinder, you will see less scenery than using wide-angle lenses, but at this time you lost the original depth of field. Simply put, in order to get the magnification, the depth of field is lost.
The above description also explains 3rd points. For any determined lens and the determined aperture F, the depth of field is also reduced while shortening the distance from the lens to the subject. When you get closer to the subject, you will see smaller scenes through the lens. We assume that you are shooting trees and flowers on the hillside. You can shoot with any lens, assuming we use a 35-70 mm zoom lens 70mm end and F / 16 shooting, the depth of field is about 100 yards. Now we move the location, close to it, in order to shoot a separate tree with 70mm and f / 16. Now the depth of field will be measured with feet (1 yard = 3 feet = 0.9144 meters). Let us move near to shoot a twig on the tree with 70mm and f / 16, and the depth of field will be calculated in inches. Continue to close, when we shoot a flowers under the tree with the same focal length and aperture, the depth of field will be measured with a fraction of the depth. Once again, we lose the depth of field in order to get a larger image.
However, if the image of the subject remains unchanged, no matter what the lens is used, as long as the aperture size is the same, the same depth is obtained. Maybe you have heard of a statement, wide-angle lens has a relatively large depth, and the telescope has a relatively small depth of field. This kind of saying is not completely accurate. When the shooting position does not change, the wide-angle lens can take a wider perspective than the telescope, while the telescope can only shoot part. This is what the second point is said. However, when the picture of the subject remains unchanged, all the lenses produce the same depth at the same F value. Take a photo with a 50mm lens, then retreat to the distance to the subject to the subject's distance, then you can use 200 mm lenses to shoot the subject of the same picture (at this time the focal length is 4 times a 4-fold). If the two lenses are set, the depth of the two photos is the same. If the distance is retired back, use 400 mm lens and the same aperture value, and a photo of the same depth of field can also be taken. If you stand in the position of the photo with a 50mm lens, approach half of the distance, use 25mm lens and the same aperture, the depth of field is still constant. These photos look great because of different views of the view due to different views of the lens, and the perspective effect is different, but the depth of the photos is the same. Now let's go back to the original question: Do you need a big depth of field or a high-speed shutter speed? In many cases, the setting of exposure parameters must be compromised between your desired imaging results and the shooting environment. Maybe you like to use F / 22 to shoot landscape, but the result is that you have to use a slow shutter, so that the grass blown by the wind is blurred. Alternatively, you like to use a shutter to shoot the bird's instantaneous action using at least 1/500 seconds, but the result is because the depth of field is small, resulting in only the bird's head in the focus range. Comfort, compromise ... But you must make a decision after thinking about it. In general, when shooting the scenery, you need to select a suitable aperture to get the appropriate depth of field, and then determine the corresponding shutter speed. Therefore, the scenery can be considered to be aperture priority. For shooting animals, you need to select the required shutter speed and then determine the aperture size. Therefore, animal photography requires the use of shutter priority.
No shutter speed or aperture size can be suitable for all shooting. I have heard that some photographers advocate the smallest aperture scenery that always uses the lens, because you can get the largest depth of field, but I don't agree with this view. To select a suitable aperture F value based on your desired depth of field. Whenever, there is no need to narrow the aperture until you exceed your needs. If the depth of the exposure value of 1/60 seconds and F / 11 can already meet your needs, continue to shrink the aperture to F / 32, but will increase the possibility of blurring photos, such as camera or subject slight shake, etc. . In fact, it is usually possible to obtain the earlier imaging as long as the aperture value is contracted with the largest aperture of the lens. But if this aperture cannot generate the depth of field you need, why do you want it? Using modern lenses and negatives, you can get the imaging results you want in any F value. When discussing how to make photos clearer, use a stable tripod more useful than shrinking aperture.
