Correct selection of ISO aperture in the room. Equivalent exposure pairs. Light as a photographer's material

Diaphragm- a special mechanism that regulates the size of the hole in the lens. The diaphragm works like the pupil of the human eye. After all, when we go out into the light, the pupil noticeably narrows, letting in less light. When we are in the dark, the pupil dilates so that as much light as possible enters the eye. With the diaphragm - everything is the same. When the lighting is poor, the aperture usually needs to be opened to allow as much light as possible into the lens. When shooting in bright light, the aperture closes. It looks something like this.

The aperture value is measured in fractional values, showing the ratio of the diameter of the entrance hole of the lens to the focal length. Aperture values ​​are usually written like this: F / 2.8, F / 5.6, F / 11, well, or like this: F 2.8, F 5.6, F 11. The value of the depth of field is directly related to the aperture value. And the rule is very simple: the more the lens is closed by the aperture, the greater the depth of field (it is often written as DOF ​​- depth of field). At the minimum aperture, the depth of field is very small, and this effect is used to create portraits or to highlight some object in the frame (not necessarily, by the way, in the foreground). Here, for example, the aperture is fully open, the focus is on the central glass, and the rest of the glasses and the background turned out to be unsharp, creating the desired effect.

Another example of a sharp object in the foreground and a blurry background.

This technique is also actively used when creating artistic portraits: sharpness is brought to the eyes, objects behind are out of focus and create the desired effect.

Here, I used F5 to make both the soldier and the boy sharp, while blurring the background.

When shooting architecture, landscapes, multi-layered compositions (for example, people at various distances from the photographer), it is necessary to use large aperture values, such as F 5.6 - F 16, to obtain the desired depth of field. Here, for example, is a multi-layered photo from Montserrat, where an aperture of F 8 was used to obtain the desired depth of field.
It should be borne in mind that the depth of field (at any aperture) is the smaller, the closer the focusing object is to the camera. That is, if the object is very close to the lens, then even at large apertures, the depth of field will be small. And if the focus is on a small object, then even with a fully open aperture, the depth of field will be quite large. Some lenses (especially old ones) have markings that very clearly show the depth of field when using certain aperture values. This lens, for example, with aperture F 22 DOF will be from about 0.8 meters to infinity. And with aperture 11 - from 1.5 meters to infinity.

The type of blur in the background depends on the structure of the aperture (the number of petals) - photographers call this blur an unpronounceable word bokeh. Here is a photo I took with a Nikon DF with a 50mm/1.8 lens.
With the aperture of the lens, one must remember that "a lot of good is also not good." In the sense that a very closed aperture, although it gives a greater depth of field, but due to various optical laws, it can degrade the quality of the image, so it is best to use aperture values ​​​​in the range from 5.6 to 16, no more. The next parameter, which is very important to get the desired result, is excerpt. Exposure - the time interval for which the shutter of the camera opens so that the image through the lens hits the camera matrix. In the old days, when photographs were taken on photosensitive plates, the shutter speed at which the photographer opened the lens cover (there were no shutters then) was tens of minutes, or even an hour.

In modern cameras, the shutter speed is usually tenths, hundredths and even thousandths of a second, which allows you to get high-quality pictures without using a tripod. The more the aperture closes, the slower the shutter speed should be. And vice versa - the more the aperture opens, the lower the shutter speed should be. When shooting handheld, the shutter speed should not exceed 1/80 second - otherwise, blurring the frame due to hand shake is quite possible. Also, the maximum shutter speed depends on focal length lens and is usually calculated as a unit divided by the focal length. That is, for a telephoto lens of 200 mm, the shutter speed should be no more than 1/200. (Well, there are several other factors at work here: the weight of the camera, the amplitude of hand shake, and so on.) If the camera or lens has a stabilizer, then without blurring you can shoot at slower shutter speeds - 1/60, 1/30 and more. Image blur can be used as a special technique, especially when shooting at night: stationary objects will be sharp, and passing cars with their headlights will be blurred, creating an interesting effect. If the camera or the subject is moving (shooting from a train, shooting sports), then the shutter speed should be very small (short), and the faster the subject moves. In this frame, the shutter speed was set to 1/800 so that the figures of dolphins were not blurred.

If the shutter speed is not chosen correctly, then the photo may be spoiled - as in the example below, where 1/30 is too slow a shutter speed for movement in the frame.

If the lighting is bad and even at a fully open aperture you have to take a slow shutter speed - here you need to use a tripod (of course, this only applies to static scenes). This shot was taken with a shutter speed of 3 seconds from a tripod.
And the last most important parameter when photographing is the photosensitivity of the matrix. ISO sensitivity is measured. Here are the standard ISO values ​​​​for various cameras:

100, 200, 400, 800, 1600, 3200.

ISO 50 is occasionally found, and various high ISOs are also used - 6400, 12800, 24000, up to ISO 102400, although only very expensive cameras can shoot at such high ISOs. In film cameras, the photosensitivity depended on the film itself and for a particular film it was a constant unit - the photographer selected the shutter speed and aperture ratio for the film sensitivity using a special device called a light meter, or simply the corresponding tables. For digital cameras purely physically, an increase in the ISO value means an increase in the signal received from each pixel of the matrix. As the signal increases, noise increases - extraneous signals that are not related to the subject. As a result, so-called "noise" appears on the final frame - artifacts in the form of dots. Here is a photo taken on a smartphone - at the same time ISO 2000 is set. Even the reduced image shows how strong the "noise" and interference are there.

Well, here is a piece cut from the full frame on a scale of 1: 1. The "noise" is just awful. But it is not surprising.
The value of the maximum working ISO depends on the physical size of the camera's matrix and on the size of the pixels of this matrix. We talked in detail about the sizes of the matrices in this article, so you should already have an understanding in this matter. So, for tiny smartphone matrices, as a rule, the picture starts to "noise" already at ISO 400-800. The same applies to conventional digital cameras, where the matrix is ​​not much larger. Good mirrorless cameras and amateur DSLRs with matrices with a crop of 1.5-2.7 get quite decent results at ISO 3200 and even ISO 6400 (for crop 1.5). Full frame cameras usually give good quality at ISO up to 12800. Here is a photo taken on a Full Frame camera (Nikon DF) with ISO 12800.

Specialized cameras like Sony Alpha A7S, where the FullFrame matrix contains 12 million large pixels, seems to allow you to shoot at ISO 25600, ISO 51200 and even ISO 102400, but there one camera without a lens costs about a hundred thousand rubles. All three parameters - aperture, shutter speed, ISO - are interconnected. To get good image quality, it is desirable to make ISO as low as possible (there will be less "noise"). However, in poor lighting conditions, even with a wide open aperture at low ISOs, you will have to use very slow shutter speeds, which will lead to blurry images when shooting handheld. As a result, you have to reduce the shutter speed to acceptable values, but at the same time increase the ISO. If the ISO is increased to an acceptable maximum, but the picture still turns out very dark (many modern devices have a Live View mode that will show you the photo on the screen as it should turn out when shooting) - then you have to either increase the ISO, risking getting noticeable "noise" "in the photo, or increase the shutter speed and shoot from the stop or from a tripod. In principle, the difficult task of setting these three parameters can be solved by the camera's automation, which is what novice photographers usually use. In addition, all cameras have special preset modes: landscape, portrait, sports and so on. And for these modes, the camera program sets the parameters exactly as we discussed above: for a portrait it opens the aperture, for a landscape it closes the aperture, for sports it first of all reduces the shutter speed. However, automatic modes are only suitable for the simplest typical scenes. As soon as you go beyond mindlessly clicking on the shutter button and you have plot photos, you can no longer rely on automation and you have to control the aperture, shutter speed and ISO settings that are set when shooting. Example. You take pictures of children playing. Beginning photographers set the "Portrait" mode for this and get blurry and blurry frames. After all, children are actively moving, so they need to be shot with fast shutter speeds, like sports stories. Another example. You make a group portrait: several people sit in the first row, the rest stand in the second row. Can I set the "portrait" mode here and open the aperture completely? No, you can’t, because the depth of field will be very small and you will only get sharp faces in one row. In this case, the aperture should be set to at least 5. 6 - to get the desired depth of field. And this is despite the fact that you are, in fact, shooting a portrait, albeit a collective one. Well, and, for example, landscape photography. You are shooting an old castle located on the opposite bank of the pond. In the frame, the reeds growing in the pond come to the fore on the left and right. If the lens should be properly apertured, as is usually done with landscape photography, the reeds in the foreground will become sharp enough to detract from the castle in the distance. If the aperture is opened, as when shooting portraits, then the reeds in the foreground will be blurry, unsharp and attention when viewing the photo will focus on the castle in the distance, which is what we need. So, as you can see, far from all scenes, the camera’s automatic will set , what you need. It works normally only on primitive scenes. Most often, the photographer manually sets the parameter that is most important for a given scene, and allows the camera to set the rest of the parameters. All cameras have the following modes: aperture priority, when the aperture is set manually, and the rest of the parameters are selected; shutter priority when shutter speed is set manually. Well, the ISO value can be manually set by the photographer if necessary. I usually shoot at aperture priority (A), and often manually set the ISO value. You can also shoot in the automatic mode (P), if necessary, manually setting the desired parameters (the same ISO) and controlling the ratio of aperture and shutter speed (in P mode, this pair can be changed in one direction or another).

If you are tired of your camera's boring auto mode and want more creativity, then it's time to get acquainted with the basics of exposure. In this article, we will tell plain language what is exposure and its three whales: aperture, shutter speed, ISO (sensitivity).

Every experienced photographer knows that you need to be able to properly adjust the exposure settings. And what is it? Exposure is a parameter that shows the amount of light entering the camera's matrix at the time of shooting. When the exposure is built correctly, then its value is zero. If there is not enough light, then it goes into minus. And when the overexposure of the frame, then a plus. On SLR cameras it is depicted as a horizontal scale, in the center of which is zero.

To achieve the optimum exposure level, the camera has three settings that can be controlled. We are talking about aperture, shutter speed and ISO sensitivity. The ISO value controls pure light, but the aperture and shutter speed also affect the artistic look of the photo. Let's talk about these values ​​in more detail.

Aperture - first among equals

The first and most popular setting that photographers like to control is aperture or aperture. The first word is Latin and the second is English. In the Russian version, they are translated as a partition or hole. The diaphragm itself is the hole in the lens that opens and closes, thereby affecting the amount of light entering the matrix. But the most interesting thing that aperture affects is everyone's favorite background blur, the so-called bokeh.

An example of a photo on an open aperture

Aperture is denoted by the letter "F" and has values ​​from one and above. The smaller the number, the more the aperture is opened. At an open aperture, the maximum background blur is achieved. If you want to get the sharpest possible shot, then you need to close the aperture.

Endurance is the lord of time

The next important element of exposure is exposure. This is the length of time the shutter will be open when the shutter button is pressed. If the aperture restricts light by narrowing the area through which it can pass, then shutter speed limits it in time. It would seem that everything is simple, adjust the shutter speed and aperture to get the right amount of light and that's it. But, with the same amount of light and different proportions of aperture and shutter speed, the result in the photo will be different. Shutter speed, like aperture, affects the image in the frame. It has a "freeze" effect. With a short shutter speed, the water jet will be frozen and you can see every drop, and with a long exposure, the jet will be smoothly lubricated and look more like fog than water.

Long exposure waterfall

Exposure is measured in seconds. It is denoted as follows: 1 is a second, 2 is two seconds, 1/125 is one hundred and twenty-fifth of a second, and so on. The smaller the value, the faster the shutter speed.

ISO sensitivity - less is better

The last parameter is ISO. It does not affect the artistic component of the frame in any way, it only affects its quality. The lower it is, the better. The ISO value displays the sensitivity of the camera matrix. The more we increase the matrix sensitivity, the more noise will appear in the frame.

Sensitivity is referred to as ISO. The minimum value is usually 100. The maximum value is different for all cameras.

Below is a visual table showing which parameter affects what.

To sum up: how to work with aperture and shutter speed

Depending on the task of the photographer, he can choose aperture or shutter speed as a priority. ISO is never a priority, as it is used as a necessary measure when it is impossible to achieve required amount light using the first two parameters. This does not mean that ISO should always be minimal, just that it should not be abused.

What is aperture or shutter priority? This is when you set one parameter, and the second is already adjusted to it.

• Aperture priority - set if you need to blur the background or sharpen the frame.
• Shutter priority - set if you need to freeze the frame, or give it dynamics.

In any mirror and mirrorless camera there are two such semi-automatic modes. You set the priority parameter yourself, and the camera adjusts everything else for you. It is with them that it is recommended to begin your acquaintance with the exposition.

ISO aperture and shutter speed table

Table of shutter speed and aperture values ​​for different weather conditions

It is not necessary to take this table as a standard, it only serves to understand the principles of the relationship of these parameters. Focus less on all sorts of tables, and practice more, experiment and enjoy your favorite pastime.

What is shutter speed, aperture, ISO sensitivity. Introduction to exposure

While this word may seem unfamiliar and even intimidating to some, we encounter exposure every time we take a picture of something. Because exposure is the total luminous flux that hits the matrix during the exposure time.

If the matrix got too little light, then such a frame will turn out to be too dark, that is, underexposed or underexposed. Here is an example of such a frame:

Comments, as they say, are unnecessary. The first desire that arises when viewing this photo is to lighten it up! But, trying to add brightness, we will inevitably encounter a loss of quality. In dark places (shadows), the matrix received such a small luminous flux that information about the color of these fragments is partially or completely absent.

When trying to lighten up an underexposed image, we get a guaranteed distortion of shades in the shadows, as well as a high level of color noise.

On the contrary, if the matrix received too much luminous flux, then the photo turns out to be too light, that is, overexposed or overexposed. Overexposure is an even greater evil than underexposure. If an underexposed image can be somehow corrected in Adobe Photoshop, then an overexposed image is much more difficult to save, and in many cases completely impossible. With underlight, we have a lack of information about dark areas. However, the information is there. There is simply no information about the color in the overexposed area - the processing program perceives it simply as an absolutely white section of the picture. And no matter how perfect the image processing algorithms are, none of them will be able to "invent" those details that were lost during overexposure.

Below is an example of an overexposed image.

The picture shows that the hull of the yacht has lost all the details and has become just a white speck. As we will not try to darken it, the lost details will not return back.

These two examples show that when photographing, you need to somehow strike a balance between overexposure and underexposure, that is, ensure the correct exposure. In this case, the photo will be balanced in highlights and shadows and will look its best.

How to ensure the correct exposure?

The exposure is set by three parameters:

Excerpt

Diaphragm

ISO sensitivity

Excerpt- this is the time period when the camera shutter is open and the matrix receives a light flux. The longer the shutter speed, the more light flux the matrix receives, the brighter the photo is.

Diaphragm- this is a mechanical "pupil" of the lens, which can open and close, thereby changing the intensity of the light flux falling on the matrix. When the aperture is open (dilated pupil), the luminous flux is maximum, when the aperture is closed (constricted pupil), it is minimal.

ISO sensitivity- the degree of susceptibility of the matrix to light. Changing this parameter allows the matrix not to be "blinded" by daylight (for this you need to set low sensitivity) and not to suffer from "night blindness" in a dark room and take shots without a flash in it (for this you need to increase the sensitivity).

These three parameters set the exposure.

If we draw a parallel between these seemingly complex things and our everyday life, I offer a very clear example. Suppose we have a glass and we need to fill it with tap water. This can be done in two ways - turn on the pressure more powerfully and fill the glass in 1 second, or draw water in a thin stream for a minute. In this case, a glass is a matrix cell, water is a luminous flux, a faucet is a diaphragm (the wider the hole, the stronger the flow). And the time it takes to fill the glass is exposure. But if we fail to fill the glass in the allotted time - the only way to comply with all the "formalities" is to reduce the volume of the glass. A glass twice as small will fill up twice as fast. Thus, the glass volume is the reciprocal of the sensitivity. Less volume (glass fills faster) - higher sensitivity (you can shoot with a faster shutter speed).

So, what needs to be done so that the glass is filled "up to the rim", that is, the photo is correctly exposed?

Exposure must be measured first

In modern cameras, all this trinity of parameters can be set automatically. In most cases, automation works flawlessly, so many do not even think about setting something up and changing something. But in a number of cases, the automation does not work correctly and we begin to look for the cause ... After reading the instructions for the camera, we find out that automatic metering operates according to one of several algorithms. Each of them is "sharpened" for different lighting conditions. Here are the main types of exposure metering algorithm...

• Integral (matrix) metering
• Partial and spot metering
• Center-weighted metering

What is the difference between them and which mode is better to use? Let's look at the table...

	Integral (matrix) metering	Partial, spot metering	Center-weighted metering
Measurement area	Exposure data is taken from the entire area of ​​the matrix and averaged. Based on this "arithmetic mean", shutter speed and aperture are set.	Exposure data is taken only from a small area in the center of the frame (with partial metering, the area is larger, with spot metering, the area is smaller). Illumination at the edges of the frame has no effect on exposure calculation	Exposure data is taken from the entire frame, but the area in the center has the most weight. The closer a point is to the edge of the frame, the less of an effect it has on the final exposure.
When is the best time to apply	The main mode for shooting when the illumination in the frame is more or less uniform and there are no objects that are strongly "knocked out" from the overall tone.	When the key object in its illumination is very different from the general background and it must be well developed. An example is a portrait of a man in dark clothes against a dark background.	As a rule, according to the result, the result differs little from the integral measurement. However, when shooting contrasting scenes, more attention is paid to the exposure of the central part of the frame.
When not to use	If the brightness of a small object differs significantly from the brightness of the background, there is a risk that the object will either be overexposed or underexposed. In this case, it is better to use partial or spot metering.	It is not known what got into the small measurement area - white snow or dark branches. The result is an almost unpredictable exposure level when shooting "motley" scenes.	There are no obvious restrictions, you need to look at the situation. It is important to remember that sometimes it is impossible to work out both light and dark areas at the same time. If the difference in illumination between objects is too large, then we use additional lighting (for a portrait) or shoot in HDR (landscape).

After measuring the exposure, the automatic device sets the exposure couple - shutter speed and aperture. Numbers appear in the camera viewfinder, for example:

This means that the shutter speed is 1/250 second, the aperture is 8. The device is ready to shoot, we just have to press the shutter button!

Exposure can be adjusted...

It happens that automatic metering is wrong and the photo has a slight overexposure or underexposure. In this case, you can correct the exposure metering and reshoot the scene so that the next frame is normally exposed. But here's the question - how to determine if there is an error in the exposure on the captured frame? Indeed, on a small LCD screen, often with less than perfect color reproduction, there is little to see! And here a wonderful function comes to our aid - viewing the histogram.

A histogram is a graph showing the distribution of brightness in a photograph.

Here is an example of a still image and its histogram:

In this case, you can see that the histogram "rests" on the left edge - this means that there are underexposed objects in the photo that look on the verge of blackness. At the same time, you can see that there is some free space to the right of the graph. To get rid of the underlight, let's try to correct the exposure by +1/3EV (this is equivalent to the fact that we increase the shutter speed "by 1 click of the wheel", that is, by 1/3 of a step).

To enter exposure compensation, we need to find a button on the camera with the following icon:

Keeping this button pressed, turn the control wheel, or press the joystick (different devices have different ways). The screen will display a slider that can be moved left or right:

If you move the slider to the right, the picture will be brighter (positive exposure compensation), if you move it to the left, it will be darker (negative exposure compensation).

Here is a variation of the previous shot taken with positive exposure compensation.

We see that the picture brightened a little, the shadows on it improved. The histogram moved slightly to the right. If you make a big correction, then the shadows will be worked out even better, but the clouds will be overexposed, that is, they will lose their shades and go white. In this case, the histogram will shift even more to the right and will be "cut off" from the side of the highlights. Thus, we derive an important rule:

Ideally, the histogram should not appear clipped either on the left or on the right. If the histogram is clipped on the left, there are underexposed areas in the photo and there is loss of information in the shadows. If the histogram is cropped on the right, then the photo is losing hues in the light areas.

Sometimes a situation arises when the histogram rests both to the right and to the left - in this case, the image loses details in the shadows and in the highlights at the same time.

Questions and tasks for self-control

1. What types of metering do you have on your camera?
2. Experiment with exposure metering modes. Which scenes are better obtained in the integral metering mode, which - in the spot or partial mode?
3. Find out how your camera's exposure compensation function is enabled.
4. Take pictures of the same scene with positive and negative exposure compensation, follow the changes in the histogram.

• What are A (Av), S (Tv) and M modes, definition of each;
• In what situations it is worth choosing each of them and why;
• Some advantages of modes (Av) and S (Tv) compared to manual tuning;
• Some of the benefits of manual configuration and examples of situations where this is the only possible option.

Manual shooting modes, what are they?

Manual Mode (M): This mode gives you full control over the three camera settings that determine exposure (known as the exposure triangle) – ISO sensitivity, aperture, and shutter speed. In the guide, we will focus on each of the options.

Aperture Priority (A on Nikon, Av on Canon): This mode gives you control over two settings, namely ISO and aperture. The camera will automatically detect the appropriate shutter speed to provide you with the correct exposure.

Shutter Priority (S on Nikon, Tv on Canon): This mode also gives you control over two exposure settings, but this time it's ISO and shutter speed. The camera will automatically determine the appropriate aperture value for your settings.

There are other factors that affect the result, namely the metering used and the exposure compensation. We will dwell on this a little later.

How to decide which mode to use?

I use aperture priority and shutter priority more than any other. When deciding which one to choose, you should consider what you are shooting, under what external conditions and what effect you want to achieve:

• Choose aperture priority mode when you want to control the depth of field (DOF). So, for example, if you are creating a portrait with beautiful bokeh, then set the aperture to f2.8 or f1.8. Aperture-priority mode should be selected not only when creating a pleasant blurred background, but also in cases where, on the contrary, you want to take a clear picture by choosing an aperture value of f11 or less.
• Shutter priority mode should be preferred when it is important for you to control the movement of the subject., that is, either to make the subject very clear while moving, or vice versa to blur it qualitatively. Thus, when photographing sporting events, concerts or wildlife When clarity is important, the shutter speed should be set to at least 1/500. When photographing the movement of water, or a car at night, the exposure interval must be chosen much longer, at least 2-5 seconds.
• There are several cases where the best option shooting will be in manual mode. So, if you are doing a night portrait or landscape, working in a studio, or taking an HDR shot using a tripod, also in some cases when a flash is used (for example, when working in a dark room, you still want to preserve some natural light) .

Here are some sample images taken with each of the modes described above.

Photo taken in aperture priority mode

Photo taken in shutter priority mode

Photo taken in manual mode at night

Things not to be forgotten

ISO: Remember that when choosing any mode, you are still adjusting the ISO sensitivity yourself.

You need to choose the sensitivity based on what kind of lighting you are shooting in. For example, when shooting in bright sunlight, it is better to set the value to 100 ISO or 200 ISO. If it's an overcast day, or if you're shooting in the shade, it's best to set the value to 400 ISO. For shooting indoors with poor lighting, the value should be set to more than 800 ISO, depending on the circumstances. Values ​​above 3200 ISO are set in special cases, for example, if you shoot a subject in motion without using a tripod and at the same time, the level of illumination is low. Using a tripod allows you to set lower ISO values, since the risk of making a blurry frame is reduced to almost zero.

Check the shutter speed in aperture priority mode.

If the camera determines the shutter speed on its own, this does not mean that you will be able to take a high-quality picture, so it's better to check once again what speed your camera has set. Yes, mostly there are no problems, but if you set up the camera and set the sensitivity to 100 ISO, at f16 in a dark room, then you will shoot with a rather slow shutter speed, and if a tripod is not used, then the frame will most likely come out blurry. Therefore, make sure that the shutter speed is set correctly, for this you can use the following rule - 1 / focal length = shutter speed. That is, if you shoot at a distance of 200 meters, then the shutter speed should be 1/200. Knowing this rule, you can adjust your ISO and aperture settings so that the shutter speed is automatically set to the value that works best.

Shot taken in manual mode with HDR

Watch for exposure warning notifications in S and A modes.

Your camera is pretty smart, but it can only work within its limits. own limitations. Therefore, sometimes you may receive messages that you are going beyond those parameters when it is possible to set the correct values ​​for automatic settings. Such a message will be displayed as a flashing warning in the viewfinder. Here are examples of such cases, both in shutter priority and aperture priority modes.

Scenario #1 aperture priority mode. Let's say you decide to set ISO 800 and F1.8 on a bright sunny day, as a result, the camera will tell you that the frame is too bright. The camera cannot set the appropriate shutter speed (fastest). If you do take a photo, make sure it's overexposed, which is what the camera warned you about. Choose a lower ISO or set a smaller aperture and try again until the warning disappears.

Scenario #2 Shutter priority mode. Let's say you are shooting in a dark room with ISO 400 and 1/1000 sec, in which case the camera will not be able to set the correct aperture value, you will be notified about this through a message in the viewfinder. The solution to this problem is to select a slow shutter speed and probably a higher ISO sensitivity, such that the warning disappears.

This article discusses such basic concepts as shutter speed and aperture. An exposure table is also provided, using which it is easy to select the correct aperture value at a given shutter speed and vice versa, which correspond to the correct exposure.

The picture above shows the shutter speed, and on the right is the aperture value. On most cameras, exposure can be adjusted by changing both aperture and shutter speed. In the first case, the intensity of light passing through the lens, or the illumination of the photographic material, is regulated, in the second, the time of exposure to light on the photosensitive emulsion layer of the photographic material (if the camera is film). However, by changing the shutter speed and aperture, you can not only ensure the correct exposure, but also control the depth of field and the movement of the subject.

First, a few general definitions: Excerpt- the time interval during which the light acts on the area of ​​the photosensitive material to give it a certain exposure. Exposure time- the time interval during which the camera shutter is open to receive a frame (frame exposure), that is, during which light acts on a photosensitive material within the entire image field. Diaphragm- a camera lens device that allows you to adjust the relative aperture, that is, change the aperture ratio of the lens - the ratio of the brightness of the optical image of the photographed object to the brightness of the object itself, as well as set the required depth of field.

This figure shows the reduction of an 8-blade aperture. Left fully open.

Exposure scale

Many modern cameras use a standard shutter speed scale in fractions of a second, and for short shutter speeds (less than 1 second), the numerator is omitted, and the shutter speed is described by the denominator:

• 8000 (1/8000s)
• 4000 (1/4000s)
• 2000 (1/2000c)
• 1000 (1/1000s)
• 500 (1/500 s)
• 250 (1/250 s)
• 125 (1/125 s)
• 60 (1/60s)
• 30 (1/30s)
• 15 (1/15 s)
• 8 (1/8s)
• 4 (1/4 s)
• 2 (1/2 s)

Aperture values

Standard aperture values ​​(relative aperture) are based on increasing or decreasing the illumination of an optical image by a factor of two: 1/0.7; 1/1; 1/1.4; 1/2; 1/2.8; 1/4; 1/5.6; 1/8; 1/11; 1/16; 1/22; 1/32; 1/45; 1/64. The numbers indicated on the lens or set on the camera (5.6; 8; 11 ..) are called aperture numbers.

Exposure control

The aperture control ring is calibrated in such a way that when the aperture is closed to the next value, the illumination of the film is halved. The shutter speed head is calibrated in the same way, i.e. it maintains a ratio of 2:1 between adjacent shutter speed values. Using the exposure table below, you can find that for given lighting conditions, the correct exposure is achieved at a shutter speed of 1/60 s and an aperture of 1:5.6. By setting these values ​​​​on the camera, we get a correctly exposed transparencies. But it turns out that a correctly exposed transparencies can also be obtained with a shutter speed of 1/125 s and an aperture of 1:4 or 1/30 s and 1:8, i.e. with any equivalent combination.

Shutter speed/aperture ratio table

Exposure, s	Aperture value
1/500	1:2
1/250	1:2.8
1/125	1:4
1/60	1:5.6
1/30	1:8
1/15	1:11
1/8	1:16

The ratio between shutter speed and aperture value that corresponds to the correct exposure. The above diagram shows that for each amount of "closing" of the aperture, the exposure time, i.e. shutter speed must be doubled to get a constant exposure value. The choice of one of the possible aperture-shutter combinations should be made taking into account the nature of the subject, as well as the author's interpretation of the plot. The fact is that the quality of transmission of any type of object movement will depend on the choice of shutter speed, and the depth of the sharply depicted space will depend on the choice of aperture.

Controlling Motion and Depth of Field

To choose the best shutter speed, you should analyze how the movement of the subject will be conveyed in the picture. Suppose, for example, that the subject is a car that is moving across the field of view at a speed of about 100 km/h and the image is taken at a shutter speed of 1/30 s. During the time that the shutter curtains are open, the car will travel almost 1m, and as a result, its image will be blurry on the film. If you reduce the shutter speed to 1/500 s, the car will move only 5 cm, and the resulting image will be sharper. The need to use low shutter speeds arises in sports photography, when it is necessary to "freeze" the movement. Fast shutter speeds also have to be used when moving the camera quickly, for example, when shooting from a moving car or train. And even when shooting with a stationary camera, it is better to take pictures with a slow shutter speed in order to avoid the inevitable small movement of the camera when the shutter button is pressed. Changing the aperture during photography primarily affects the depth of field, that is, the distance between the objects closest to the camera and the objects farthest from it, within which the details of the plot appear equally sharp in the picture. The smaller the diameter of the active aperture of the lens, the greater the depth of field. When photographing many scenes, a large depth of field, i.e. very sharp rendering of details both in the foreground and in the background is extremely important. For example, when shooting landscape photography, a photographer can build his composition so that a cover of flowers or other interesting details that are close to the camera is sharp in the picture, and at the same time the background is clearly conveyed. Using a small aperture will ensure that both are as sharp as possible. In cases where it is required to clearly convey only the main subject of shooting and separate it from the background, which interferes with perception main part, or highlight any detail of the image, a shallow depth of field is needed. Shallow depth of field is achieved by using a large lens aperture.

From the foregoing, it follows that it is practically impossible to “stop” the movement of an object and obtain a large depth of field at the same time, since in order to obtain a normally exposed frame to fulfill the first requirement, a low shutter speed and, consequently, a large aperture value are required, and to fulfill the second - small aperture values ​​and, consequently, long shutter speeds. In such a situation, one has to compromise by using medium shutter speeds and apertures, while neither requirement is completely satisfied.