Nothing like, and at the same time so familiar to modern man - the sound of the shutter (Shutter) of the camera. This sound has become so recognizable that it has become synonymous with photography, and has been imitated electronically on digital counterparts and mobile phones. Have you ever thought about the mysterious process behind this sound?

Shutter operation in a SLR camera

There are three main parts to a camera shutter: the mirror, the bottom curtain, and the top curtain. When you look through the viewfinder of a so-called SLR camera, you are essentially seeing the image directly from the lens as it passes through a group of mirrors. When the shutter is pressed, the mirror is raised for a short time to allow light to hit the sensor/film. That is why the picture disappears in the viewfinder - at this moment it becomes dark.

After the mirror rises up, a small shutter starts moving from top to bottom, exposing the matrix / film behind it. After that, another curtain falls down, covering the entire matrix / film. Depending on the set shutter speed, this process may change over time. Sometimes it can be very fast.

So - the second curtain closes the matrix, the mirror falls down, returning to its original place, the curtains take their original position. All this action, from the moment the mirror is raised to its return, is the shutter cycle.

reflex cameras

Shutter operation without a SLR camera

Unlike SLR cameras, non-reflex cameras do not have a system of mirrors, or a penta prism. Actually, that's why this type of camera is called without SLR. The matrix in such devices is constantly exposed to light passing through the lens. For this reason, non-SLR cameras use either an LCD screen or an electronic viewfinder.

As soon as the user presses the shutter button, the lower curtain rises to close the sensor. Then, the same shutter starts to lower, and at that moment the exposure takes place. Then the second curtain is lowered and closes the matrix. After the second curtain closes the sensor, the exposure ends and the shutters return to their original position.

Graphical example of one loop forno reflex cameras

Is a mechanical shutter required?

Before the era of digital sensors, it was very important to equip the camera with a shutter. This was due to the fact that the film cannot simply be turned on and then turned off. Photographic film and film are very sensitive to light and any, even a short light exposure to it is fraught with consequences. Of course, at present, technology makes it possible to completely dispense with a mechanical shutter in cameras of a certain category.

A classic example of such, without shutter devices, are consumer class cameras - pocket cameras and mobile phones. Cameras of this kind are usually noisier than their classic counterparts. This is due to the fact that in such cameras power is constantly supplied to the matrix. It should also be borne in mind that the higher the ISO value, the more noisy the image will be, and this applies to any type of camera.

Most likely in the near future, technology will allow you to get professional-quality images using cameras without shutters, but at the moment, they are still far from professional quality.

The mechanism of the shutter when shooting video

The mechanism of the shutter for video shooting is very different from the principles of the shutter for photography. This is due to the fact that a conventional camera is able to activate the shutter mechanism approximately six times per second. The triggering mechanism is simply too slow for video, which is typically recorded at 25 or 30 frames per second. Therefore, curtains and mirror mechanisms are always open.The shutter is implemented on the basis of adjusting the time of reading information from the matrix. This is the electronic shutter. The shutter speed, on the other hand, is determined by the time between the reset of the matrix and the moment the information is read from it. Accordingly, the matrix is ​​reset after each frame.

What is Global Shutter?

Perhaps the name hints at the fact that this is one of the shutter types, but in fact the interaction between the Global Shutter and the matrix is ​​​​a very important point. When it comes to the camera sensor, there are two main types of sensors that you need to know about - CMOS and CCD.

CMOS - CMOS (complementary structure metal-oxide-semiconductor) matrix, the most common in the category of semi-professional cameras. And I must admit, they are very problematic. This is due to the principle of operation of the CMOS matrix. It reads information from pixels moving from the top left corner to the bottom right. This creates a problem, because if the subject is moving quickly at the moment of shooting, then we get a distorted image at the output. In such conditions, Rolling Shutter (as it is called) creates a "jelly" effect, which is a marriage, if we speak from a professional point of view. And this effect is especially evident when shooting video.

Another type of matrix - CCD - CCD (charge-coupled device), records the entire frame. This is what is called Global Shutter. How Global Shutter works similar to the operation of a film camera - the frame is recorded in its entirety, thereby eliminating image deformation. In this way Global Shutter produces a more realistic and high-quality image.

What is an Obturator?

Obturator (fr. obturateur, from lat. obturo - close) - a mechanical device for periodically blocking the light flux. This type of shutter is used in motion picture cameras. As you know, a film camera records 24 separate frames per second, which means that 24 times per second the film is exposed to light. As a result, we get the illusion of movement. When shooting video, the shutters described earlier in this article cannot be used because they are too complex to be implemented 24 times per second. For this reason, the obturator was developed.

This shutter is very similar to a fan. It is located inside the camera body and, rotating, closes or opens the light flux to the film or matrix. The process consists of three stages: while the disc blocks the light, the film is set in position, then the disc is opened - the exposure takes place, at the final stage, the disc closes the frame. This process is repeated 24 times per second.

In modern cameras, it is possible to accurately select the shutter speed value. But in the case of classic film cameras, you have to calculate the shutter speed yourself. There is a concept of exposure angle (see figure), respectively, the operator calculates the shutter speed considering two parameters, shutter angle and frame rate.

For example, if you are working with film and recording at 24 frames per second, and the shutter angle is 180°, then the shutter speed will be 1/48, or twice 24. The following picture will help you understand this process.

It's not uncommon for high-end movie camera manufacturers to list shutter speeds in corners, and there are plenty of online resources that describe in more detail and accurately how film cameras work and calculate shutter speeds.

Shutter performance is one of the most important parameters a photographer controls to capture the moment. With the advent of electronic shutters for mirrorless cameras, a lot of additional options appeared in the settings menu and people began to often ask questions about what's what and why. In this article, I would like to describe in detail the principles of operation of camera shutters in order to understand what settings are needed for what and what limitations arise when working with certain types of shutters.

So, first we need to understand a little theory. The shutter is a device that limits the access of light to the matrix (or to the film, but we will not consider this technique now). Shutters can be "mechanical" (to put it correctly, it's still "electromechanical", because the time of pure mechanics has already passed, but for simplicity they are reduced to "mechanical"), "electronic" and all kinds of "combined", to varying degrees combining the principles mechanical and electronic shutters.

1. Mechanical shutter
Most often, modern cameras use a mechanical focal shutter, which stands directly in front of the matrix. There is also a central shutter, which, as a rule, is located in the lens, but we will not talk about it today, because now it is quite rare and, as a rule, in medium format systems (for example, in compact cameras, the central shutter is found in X100 series cameras from FUJIFILM, as far as I know, and in similar models).

If greatly simplified, then, in fact, the focal plane shutter is two curtains. One opens access to the matrix, and the second, respectively, closes. Well, if you get a little tedious, then it would be more correct to call this design like this: an electronically controlled focal shutter of a curtain-slit type with a vertical stroke of the curtains. But we're not boring, right? ..

If we talk about SLR cameras, then the matrix is ​​​​not involved at the time of building the frame, a system of mirrors and a prism helps us with sighting. Therefore, at the time when we aim and build a frame, for SLR cameras the shutter is closed and ready to shoot. When the shutter button is pressed, the mirror rises, the shutter opens (the first curtain moves, opening up light access to the matrix). And when the desired shutter speed is reached, the shutter closes (the second curtain falls, closing the matrix). Here's a video of how the whole system works:

But, since we are talking about mirrorless cameras, here everything is a little different. At the moment when we are building a frame, the matrix is ​​involved, it works - a signal is read from it and sent to the screen or to the electronic viewfinder. Accordingly, the shutter must be constantly open. At the moment when the shutter button is pressed, the shutter on the mirrorless camera first closes, and then the process proceeds in exactly the same way as described above: the first curtain opens up light access to the matrix, and the second closes it. Here you can see how this happens using the FUJIFILM X-Pro1 shutter as an example (in fact, the camera model is not so important, everything works in principle the same way for other mirrorless cameras):

The mechanical shutter is well known from film cameras; it is a technologically advanced design. It is clear how to work with her. However, such a shutter has a number of limitations. And the worst ones are:

• the speed of the entire node is determined by the speed of the shutters
• the impossibility of setting very short shutter speeds
• vibrations introduced into the system by moving parts of the shutter
• The shutter makes a loud noise during operation

In principle, new ultra-light and ultra-strong materials could help in the first case, and the speed of the shutters can be increased. However, in reality, the strength of the knot is not the only limit that prevents further development of the shutter mechanism. This is where it is worth talking about the second limitation, which in fact turns out to be much more unpleasant than the first. The fact is that if the shutter speed is quite long, then the shutter will work it like this: the first curtain opens completely -> light falls on the entire surface of the matrix -> the required shutter speed is reached -> the second curtain closes, interrupting the light flux. But if you want to set faster shutter speeds, then the shutter starts to work differently: the first curtain opens, providing light to the matrix -> only part of the matrix is ​​​​open, but the fast shutter speed has already been reached -> the second curtain starts to close when the first one has not fully opened. That is, in fact, at short shutter speeds, the shutter does not open the entire matrix, but only part of it - the slit "runs" along the sensor, exposing the frame. The narrower the slit, the less light hits the matrix and the faster the shutter speed provides. This is how it looks like:

But here's the problem: if the gap is very, very thin, then, in addition to problems with the exact synchronization of the movement of the curtains themselves, there is also a diffraction effect that significantly degrades the quality of the resulting image. That is why, on most cameras, the fastest shutter speed with a mechanical shutter is usually 1/8000 of a second. Which means that the second curtain starts to move after the first with a difference of 1/8000 of a second.

By the way, due to the curtain-slit principle of the mechanical shutter, certain problems arise when shooting with flashes. The fact is that most flashes have a fairly short pulse length. That is, in simple terms - the flash lamp shines very brightly, but for a short time. As a rule, the pulse lasts from 1/800 to 1/40000 of a second, depending on the power. If the shutter speed is quite long, then the shutter opens the entire matrix, and then a short flash pulse is exposed over the entire sensor area. But if you want to use a shorter shutter speed, then it will already be determined, as we remember, by the movement of the shutter slit along the matrix. And the light from a short flash pulse will only expose a small area of ​​the sensor. Therefore, not the entire frame will be illuminated, but only part of it. Therefore, when shooting with flashes on cameras, restrictions on short shutter speeds are introduced: with the flash turned on, you simply cannot use shutter speeds at which not the entire matrix is ​​open. This limitation can be circumvented by using flashes that have a "high speed sync" mode. With it, the pulse is weaker in power, but lasts as long as necessary to expose the entire frame by the moving shutter slit.

The third point is shutter shock during operation, the so-called shutter shock. No matter how light the shutter curtains are, they still have weight and when moving they accelerate and decelerate, causing the system to oscillate. If at short shutter speeds small fluctuations do not interfere with the photographing process, then at moderately slow shutter speeds these vibrations already lead to microblurring and, as a result, to a drop in the quality of the resulting image. And, by the way, the larger the camera megapixel, the more it will be noticeable. Engineers are working on damping vibrations, but here one must understand that they cannot cancel the laws of physics. Here, by the way, in this slow motion video, you can very well observe the fluctuations of the shutter curtains:

Well, and finally - the mechanical shutter makes noise during operation. The same "chick-truck" that we hear when shooting. In a SLR camera, mirror clapping is also added here. But even mirrorless cameras with a mechanical shutter are by no means silent. Not all shoots allow this. For example, in theater or wildlife photography, the sound of a mechanical shutter can be quite annoying.

So, to summarize, the mechanical shutter has undeniable advantages:

• its design is clear, it has been well developed over the years
• wide range of shutter speeds available (theoretically from infinity to 1/8000 second)

• inability to use very short shutter speeds
• shutter shock
• sounds at work
• mechanism wear

2. Electronic Signer
When using an electronic shutter, the matrix is ​​​​not closed by any shutters, it always remains open. It's just that when the shutter button is pressed, the charge on the photosensitive elements is reset, the signal recording starts, and then, after a specified time, it is read. To put it even more simply, the matrix turns on to register light and turns off at the end of the exposure. All smartphones are equipped with an electronic shutter, for example. Recently, this type of shutter has become quite common on large mirrorless cameras.

Benefits of electronic shutter:

• can achieve very fast shutter speeds (up to 1/32000 for FUJIFILM X-series cameras)
• he is absolutely silent
• there is not even the slightest shaking of the apparatus from the movement of the shutter parts
• does not consume the resource of the mechanical shutter, because the curtains do not work
• it is compact, it has no moving parts

• rolling shutter effect
• banding when shooting with flashing light sources
• inability to work with flash

The solution to the problem of rolling shutter can be the so-called global shutter, "global shutter". This is a kind of electronic shutter, in which data from the matrix is ​​read not line by line, but at the same time. The difficulty of implementing a global shutter is that now the data flow from the matrices is so large that expensive solutions are required to read them in one sitting. Therefore, for now, the global shutter is used only in those systems where it is vital and where the price of equipment is not such a critical factor. For example, the global shutter is most widely used in digital cinema cameras - rolling shutter is unacceptable there, and the high price of the solution is not so noticeable against the background of the overall budget of the movie.

Second. Flashing and flashing light sources (photo flashes, lightning bolts, computer monitors, flickering fluorescent lights, and so on) can leave stripes on the frame. That is, one part of the image is much weaker illuminated than the other. The boundary between these two parts is usually very sharp. The effect occurs for the same reason as the rolling shutter. An explanation of it and an example frame can be found at the above Wikipedia link. Because of this effect, flashes cannot be used with an electronic shutter (the "Flashes" item in the menu is disabled when an electronic shutter is selected) and should not be shot in a studio. By the way, the effect does not always occur - it usually does not occur at relatively long shutter speeds.

In summary, the electronic shutter is a rather interesting solution, but so far, due to technological limitations, it is applicable either in cases where a very fast shutter speed is required, or where the sound accompanying the operation of the camera mechanisms is unacceptable.

3. Hybrid
And finally, we got to hybrids, in which they try to combine the advantages of the first two types of shutter and avoid their disadvantages. In this part, let's talk about the shutter with the "electronic front curtain" (Electronic Front Curtain Shutter). When using the electronic front curtain shutter function, the mechanical front curtain is not applied. Instead, an electronic exposure of the image sensor is started (as with an electronic shutter), which is completed by the mechanical closing of the rear shutter curtain. That is, it turns out half electronic, half mechanical shutter. What does it give us? And here's what:

• mirrorless camera does not waste time closing the shutter before shooting
• during exposure, there is no shaking of the system from the movement of the shutters
• shutter sound decreases (only one of the two curtains moves)

There are several nuances to an electronic front curtain shutter. First, when shooting at a fast shutter speed (typically at shutter speeds faster than 1/2000 second) and wide open apertures, a blurred area may appear in the image. It doesn't have to be, but it can. Secondly, in the same way, when shooting at a fast shutter speed (shorter than 1/2000 second), depending on the shooting conditions, the image brightness may be uneven. Alas, these are the costs of "combination" - the shutter mode with an electronic front curtain, albeit to a lesser extent, inherits the "sores" of the electronic shutter. And thirdly, if the lens is made by another manufacturer, then when shooting with a shutter with the first electronic shutter, it is likely that you will not be able to set the correct exposure or the image brightness will again be uneven. In all such cases, you need to switch to another type of shutter, for example, to a mechanical one.

So, now that we have dealt with the theory, we can already start explaining how shutter modes work using the example of the FUJIFILM X-H1 camera. There are several of them, you can choose from the following list:

• Mechanical (MS) . By default, the shutter speed is from 30 seconds to 1/8000 second, but in shutter priority (S) and manual (M) modes, the shutter speed can be set from 15 minutes to 1/8000 second, and in bulb (B) mode, the maximum shutter speed can reach 60 minutes. Good old mechanics! Use is recommended in most cases, especially when shutter sound is not critical, when very fast shutter speeds are not needed, and when the goal is not to clearly stabilize the image. You must also switch to this type of shutter if you are shooting with flash or in the studio.


• Electronic (ES) . By default, from 30 seconds to 1/32000 second, and also in S and M modes, it can be from 15 minutes to 1/32000 second. The mode is completely silent and allows you to use very fast shutter speeds. But, alas, it is prone to rolling shutter and the appearance of stripes when shooting with flickering light ... Therefore, this type of shutter is recommended only in cases where complete silence is needed or when very fast shutter speeds are required. At the same time, it is highly desirable not to shoot dynamic scenes and avoid flickering lighting (it is given, for example, by fluorescent lamps). Also, this shutter mode is used in situations where you want to get the most out of image stabilization systems, such as when shooting at extra slow shutter speeds handheld, without a tripod, or when shooting at slow shutter speeds. By the way, it is in this mode that the maximum rate of fire of the camera is achieved - up to 14 frames per second!


• (EF) . Exposure from 30 seconds to 1/8000 second, but in modes S and M can be from 15 minutes to 1/8000 second. This type of shutter can be used in photography when it is necessary to shorten the time between pressing the shutter button and taking the picture. This mode can also be set when a well-stabilized image of single shots is required. In fact, this is the ideal reportage shutter mode: fast, quiet, with good stabilization. The only thing to consider is that the best image quality in this mode is achieved at shutter speeds up to 1/2000 second, so it is not recommended to shoot at very fast shutter speeds with this type of shutter. However, for most reportage stories, 1/2000 of a second is more than enough.


• Mechanical + Electronic (M + E) . In this case, from 30 seconds to 1/8000, the camera will shoot with a mechanical shutter, and at shutter speeds shorter than 1/8000 second, the electronic shutter comes into play, up to 1/32000 of a second. That is, the electronic shutter only works when the mechanical shutter can no longer cope with the speed. A very convenient combination for shooting with high-aperture optics with an open aperture. This is especially true in combination with dynamic range expansion modes, which require higher ISO values ​​for FUJIFILM cameras. That is, this is an ideal mode for shooting with fast apertures with an open aperture and maximum expansion of the dynamic range, while you can easily shoot in the daytime, the camera does an excellent job with such scenes on this combination of shutter modes.


• With electronic front curtain + Mechanical (EF + M) . Here, from 30 seconds (or 15 minutes in S and M) to 1/2000, an electronic front curtain shutter will work, and after 1/2000 and up to 1/8000, a mechanical shutter will come into play. Convenient mode for reportage photography. At the most popular shutter speeds (up to 1/2000), a quieter, faster and less vibration-loaded shutter with an electronic front curtain will work, and at shorter shutter speeds a mechanical shutter will come into play.


• With electronic front curtain + Mechanical + Electronic (EF + M + E) . From 30 seconds (or 15 minutes in S and M) and up to 1/2000 the camera will shoot with an electronic front curtain shutter, after 1/2000 and up to 1/8000 the mechanical shutter will work, and at shutter speeds shorter than 1/8000 and up to 1/32000 there will be an electronic shutter in the case. Combo! All at once. Perhaps, for X-H1 this is the most interesting mode.

In all combined modes (like "EF + M + E") switching to one or another type of shutter will occur automatically, based on the required shutter speed when exposing the frame.

One of the main mechanisms of digital cameras is the shutter, its functional purpose is to pass, when the button is pressed, light rays to the matrix, which is a photosensitive element. Light rays are transmitted for a certain period of time. This period of time during which the shutter opens is called " excerpt". A feature of digital devices is the installation of shutters that can close and open at a very high speed, thanks to which the exposure time (matrix illumination) is regulated with high accuracy. For specialists, it is very important that photographic equipment has such accuracy, as well as a large range. With a slow shutter speed, more light enters the matrix. The shutter of modern digital cameras, especially for professional use, can control shutter speed well. At the same time, this element protects the matrix from flare, which can occur when reading an image, at the very beginning of the exposure.

Gate types

Closures may have differences in their design, as well as in the principle of closing. According to such features, these elements are divided into electronic and mechanical. In various models of digital cameras, an electronic shutter is installed; it is built directly into the camera sensor.

electronic shutter

At the right moment, it turns on the sensor to receive the light flux, then turns it off at the command of the processor. The operation of such a shutter is controlled by the camera's processor, its electronic equipment. When using such an electronic element, the light flux constantly hits the matrix, due to which the image from the matrix is ​​transmitted to the LCD display of the digital device. Such an image is read for a certain time, which lasts between zeroing the matrix and the moment when the electronic information is read. This time is the shutter speed, which is characterized by the camera. Thanks to electronic shutters, the photographer can use fast shutter speeds, even up to 1/15000s. The operation of the electronic shutter is characterized by the absence of noise and vibration. The only thing is that when using such a shutter, you can also observe low image quality, since the reading of the matrix cells occurs sequentially. In order to avoid image distortion, such unpleasant effects as a halo, blooming, professional photographic equipment is also provided with a mechanical shutter.

mechanical shutter

Provides additional protection of the matrix from the ingress of fine dirt and dust. It also performs such an important function as dosing light on the photosensitive element of the camera, that is, on the matrix. Thanks to the mechanical shutter, the expensive matrix retains its high technical qualities. Such a shutter is characterized by a certain service life.
Mechanical shutters are also divided into two groups - curtain and central.

Central shutter

Represents the structure of thin plates ( petals), opening towards the edges and closing in the opposite direction, so the luminous flux is distributed evenly. It is installed between the lenses of the objective. The most valuable for professionals are those valves in which the dampers open very quickly.

curtain shutters

They have higher speed and greater instantaneous exposure. The curtain shutter design uses two parts (curtains), which are separated by a gap. The light flux penetrates into it from the lens. When the slit shutter is triggered, its first curtain opens the frame window, the second closes it. The shutter speed depends on the width of the gap that is formed between the curtains. The principle of operation of the curtain shutter, in which the curtains move, can lead to distortion of some subjects in the picture. But this shutter provides processing of short exposures and has a high coefficient of action.

Electronic shutter

In digital cameras, an electronic optical shutter can also be used, which is a liquid crystal located between two polarized plates. A light flux flows through this crystal, then it enters the optical converter.
The shutter is an important element in the operation of any photographic equipment. The basic principle of operation of any kind of shutters is the opening during photography, the passage of light rays. When the light flux hits the photosensitive element, the frame is exposed. The next step is to close the shutter, which allows you to proceed to the next shot. The shutter plays a very important role in the design of a camera.

Excerpt- the time during which it remains open and transmits light for exposure of a photosensitive film or a matrix of a digital camera.

Like and , is one of the two main ways of influencing how much light reaches the camera sensor (), unlike . But in addition to the exposure value, the exposure value used depends on how the depicted object will look in the picture (Fig. 1).

Rice. 1 - Influence of shutter speed on the depicted object

With the same aperture value, a shutter speed of 1/125 s is twice as long as a shutter speed of 1/250 s. Thus, twice as much light will fall on the matrix, i.e. exposure at a shutter speed of 1/125 s is one stop more than at a shutter speed of 1/250 s.

Values ​​taken by the shutter speed of the camera

On the full-scale shutter speed scale, each step means halving or halving the amount of light: 30s, 15s, 8s, 4s, 2s, 1s, 1/2s, 1/4s, 1/8s, 1/ 15s, 1/30s, 1/60s, 1/125s, 1/250s, 1/500s, 1/1000s, 1/2000s, 1/4000s, 1/8000s.

This scale does not apply to all cameras. In some it may be more limited, in others intermediate values ​​​​of a third (1/3) or half (1/2) of the main step (1/30 - 1/40 - 1/50 - 1/60) will be used.

Shutter speeds of 1/500 s or faster are commonly referred to as " fast”, shutter speeds of 1/15 s and longer - “ slow”, shutter speeds shorter than 1/1000 - "super short".

Shutter speed display on the camera

On the display of most cameras, shutter speeds in fractions of a second, such as 1/500, are abbreviated and simply written "500". Therefore, confusion may arise, it may seem that the value "1000" indicates a shutter speed twice as long, although in reality it is half as long. When using shutter speeds in seconds, an additional sign appears near the value - 30ʺ. You need to get used to this and be careful not to confuse 1/4 with and 4".

Features of choosing the right shutter speed

When shooting handheld in low light conditions, it is necessary to limit the movement of the subject and the camera itself during exposure, as a photographic defect occurs - shaker (lubrication, shaking, pulling) (Fig. 2). To avoid such a defect, it is necessary to ensure that the denominator of the shutter speed in seconds is not less than the focal length of the lens in millimeters. For example, when shooting handheld with a 50 mm lens, you should set the shutter speed to no more than 1/50 s. When shooting with a 200 mm telephoto lens, 1/200 s.

photographic shutter

The shutter speed is controlled by the shutter of the camera.

Modern digital cameras use electronic and focal shutters.

electronic shutter

The electronic shutter is understood not as a separate mechanism, but as the principle of exposure dosing by a digital matrix. The shutter speed is determined by the time between zeroing the matrix and the moment the information is read from it. This principle allows you to achieve faster shutter speeds (including flash sync speeds) without the use of expensive high-speed mechanical shutters. This principle is also used in compact digital cameras.

The most common shutter is the focal shutter (Fig. 3). The shutter speed is controlled by the time that elapses between the opening and closing of the first and second curtains 2, 3. When the shutter is released, the first curtain 2 is moved by the mechanism 5, opening the way for the light flux. At the end of the specified shutter speed, the light flux is blocked by the second curtain 3. At short shutter speeds, the second shutter starts moving before the first one completely opens the frame window 4. The gap formed between the shutters runs across the frame window, successively illuminating it. The duration of exposure is determined by the width of the gap. The principle of the focal plane shutter is shown in animation 4.

Conclusion

Since shutter speed is one of the most important exposure parameters, it is necessary to correctly determine and control it in each specific situation. In modern digital cameras, shutter speed can be determined automatically, through the lens (TTL metering) or manually, based on metering values.

The shutter of the camera is a special mechanism that is needed to transmit light to the camera matrix for the desired period of time (exposure).

Gate designs are many and varied. The most common curtain shutter, consisting of two fabric or metal curtains, which at the time of shooting form a gap of different widths between them (depending on the shutter speed), which “runs” along the frame, allowing the right amount of light to enter the matrix.

Shutter speed is the time during which the camera's sensor is exposed to light passing through the lens.

An example of a camera shutter

The shutter speed is indicated in seconds, while they are indicated by a number with a double prime ("") instead of a decimal point, symbolizing the second (2""5, 0""8), or, much more often, in fractions of a second, and only the denominator is indicated, and the numerator is taken equal to 1, that is, a shutter speed of 60 means a time of 1/60 of a second. The symbol “B” (from the English word “Bulb”) means that the camera matrix will be open to light for an unlimited time. When the photographer presses the shutter button, the shutter opens. When the button is pressed a second time, the shutter closes. With this function, you can get exposures of several hours, which can be useful when photographing the starry sky.

electronic shutter

In early film cameras, the shutter was a mechanical device. In modern digital cameras, the shutter is made in the form of an electronic circuit that controls the process of reading information from the matrix. For ease of understanding, the electronic shutter can be represented as a special electronic circuit that supplies voltage to the matrix for a certain time (hold), while the rest of the time the matrix is ​​de-energized.

An electronically controlled mechanical shutter is often referred to as electronic.

Depending on the method of reading information from the matrix, two types of electronic shutters are distinguished: a vertical shutter (Global Shutter, the picture is formed completely) and a rolling shutter (Rolling Shutter, progressive reading technology).

With a vertical shutter, a digital image is formed instantly, just like when photographing, i.e. all pixels of the matrix allocated for work transmit information simultaneously. The operating time of the sensor is equal to the shutter speed, which is set in the camera in advance.

With a rolling shutter, a digital image is built not by instantaneous reading of information from the matrix, but by its sequential scanning. Those. information from the sensor is not transmitted all at once, but line by line - from top to bottom, while the shutter seems to slide across the frame. Again, the concept of a shutter here is arbitrary and has nothing to do with the mechanical implementation.

Simplified operation of electronic shutters can be shown in the following pictures:

The use of an electronic shutter makes it possible to achieve fast shutter speeds without the use of expensive high-speed mechanical shutters.