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 the focal length of the 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 standard values ISO 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 according to the film sensitivity, using a special device called a light meter for this, or simply the corresponding tables. For digital cameras, purely physically, an increase in 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 (Full Frame) cameras usually give good quality at ISO up to 12800. Here is a photo taken on a Full Frame (Nikon DF) camera with ISO 12800.
Specialized cameras like the Sony Alpha A7S, where the FullFrame matrix contains 12 million large pixels, seem 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 at 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, and the picture is still 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 either have to 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 - here you can no longer rely on automation and you will 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. AT this case aperture should be set 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 is properly apertured, as is usually done when shooting a landscape, the reeds in the foreground will become quite sharp and will 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. , 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).
Most modern cameras have built-in automatic modes that allow you to take high-quality pictures. At the same time, none of them will make it possible to create a truly unique photo. For these purposes, the photographer will have to take control of the settings in their own hands, including understanding what aperture and other lens indicators are.
The concept of aperture
Aperture is a structure in a lens made of semicircular spheres called petals. With their help, the flow of light to the matrix is \u200b\u200bregulated. After the user presses the shutter button, the aperture forms a user-set diameter, which will skip right amount Sveta. Aperture is marked on the lens with the letter f.
The markings on the lens can be from f / 1.2 to f / 32. The smaller the aperture value, the wider the petals will open, and the more light will reach the photosensitive element.
How Aperture Affects an Image
The aperture of the camera primarily affects photo brightness. Obviously, the wider the petals are open, the more light hits the matrix. The second point, and many believe that it is more important in the work of the diaphragm, is depth of field. The wider the aperture is opened, the objects in the background will be more blurred and vice versa, a small window for light will give a clearer picture. The depth of field of the imaged space (DOF) is a very important concept in the theory of photography, and it is directly affected by the aperture of the lens.
Thus, the larger the aperture value range in the camera, the more scope for creativity it provides. Lenses with wide range diaphragms are more expensive and larger.
How to choose the correct aperture value
At first glance, the principle of working with aperture values is clear. A wide open aperture produces a brighter picture but with a blurred background and vice versa. But there is a small problem. There are two concepts - diffraction and aberration. The general meaning of these concepts is the distortion of light and, accordingly, the noise in the photo. They appear at the limit values of the aperture.
To avoid such troubles when shooting, it is recommended to choose best option aperture value that minimizes noise. This can be done in the following way. At each aperture value, the focus is on the same subject. The aperture value options with the least amount of error are taken as the basis at the time of shooting. Usually this is 2-3 values less than the limit options. In some cases, you have to use extreme values, for example, when you need a lot of light in the photo or maximum clarity of objects.
Advice! For iris work and during search best values you need to select full manual mode (M) or aperture priority mode (Av).
Aperture in a smartphone
Modern smartphones have cameras that recent times allow you to get very high quality pictures. For some devices, you can see mysterious characters f/1.4, f/2/0 and others after the number of pixels. Smartphones have this value called aperture. Sometimes mobile device manufacturers shorten the spelling and simply write f2 or f1.4. This concept implies the size of the camera opening and works by analogy with the aperture. Logically, the aperture of the rear camera will give the best shots when the aperture value is wide enough. For a camera with an f/2.0 aperture, shooting indoors is not a problem, and the photos here often reach the level of compact cameras.
A camera lens contains several lenses. When light rays pass through them, they refract, after which they all converge at a certain point from the back of the lens. This point is called focus or focal point, and the distance from this point to the lens is called the focal length.
What does focal length affect?
First of all, this parameter affects what will fit in the frame. The smaller the value, the wider the viewing angle is, but the perspective is more distorted. A high focal length, among other things, gives background blur.
On a note! It is believed that the focal length of the human eye has a parameter of 50 mm.
Based on this, there are several types of lenses according to the size of the focal length.
- Ultra wide angle from 7 to 24 mm. Used to take photographs with the highest possible viewing angle. The 14mm lens is the most popular for landscape photography. Blurring the background with such a lens is almost impossible.
- Wide angle - from 24 to 35 mm. The lens has less perspective blur compared to the previous one, but the angle of view is also smaller here. It is used for shooting on the streets of the city, group porter photos and sometimes for landscapes.
- Standard - from 35-85 mm. Suitable for shooting a person in full height, landscape, and for most ordinary photographs without a subject. You can not shoot portraits, as the lens distorts the proportions of the face
- Telephoto lenses - from 85 mm. From 85 to 135 mm there is almost no distortion, this is the best option for shooting portraits. After 135, the space shrinks, which is also not suitable for shooting faces. Telephoto lenses are suitable for shooting subjects that are difficult to approach. It can be sports events, wild animals and other objects.
As a rule, a lens with a focal length of 18 to 55 mm is sold with the camera. These lenses allow you to capture the most different photos. In fact, this is a universal option.
How to set focus
In order to set focus, you first need to understand what the photographer wants to see in the picture. Based on this, specific values should be set on the lens. To get the main subject clear and the background blurry, you should choose a small focal length value, for example, for an 18-55 lens closer to 18. If you need to get a clear foreground and perspective in the photo, then the principle will be reversed accordingly.
After that, in the viewfinder you need to find the desired point and focus on it. This function Most modern cameras have it. Depending on the manufacturer and model, focus points there may be many. The camera captures not only the main object, but also those closest to it.
Focus modes
Majority SLR cameras have several focus modes that are used for different purposes. The focus settings have the designations S, AF, MF. Let's see how they are decoded.
- "AF-S" - Auto Focus Single, which can be translated into Russian as "single aftofocus". Its essence lies in the fact that when the shutter button is pressed halfway, the lens focuses and stops when a successful option is obtained.
- "AF-C" - Auto Focus Continuous, which can be interpreted as continuous autofocus. In this case, when the button is pressed halfway, the camera continues to follow the focus even if the composition changes or objects move at that moment.
- "AF-A" - Auto Focus Automatic, auto focus. The camera itself chooses one of the two previous modes, many beginners shoot on it and are unaware of the existence of other options.
- "MF" - Manual Focusing, manual focus, an essential option for advanced photographers. Here, focusing is done by rotating the ring on the lens.
Manual focus is available on models that do not have a focus motor. It is enabled from the camera menu. Often the camera does not accurately focus on the object, this can only be corrected in manual mode.
Obviously, it is impossible to choose the correct focal length in the lens, as it will differ for different types shooting.
What is zoom
Zoom (Zoom) is an integral characteristic of each lens, which is directly related to the focal length. In order to get the zoom value for a particular lens, you need to take the range of focal lengths, and divide the larger by the smaller. For example, for an 18-55 lens, the zoom is 3. This value characterizes how many times the object being photographed can be enlarged.
Zoom in the camera can be divided into two types:
- optic;
- digital.
This concept is most commonly used for SLR devices with interchangeable lenses. In this case, in order to enlarge or reduce the object, it is necessary to move the lenses in the lens “by hand”, while all other set values do not change in any way. Thus, the optical zoom does not affect the final photo.
The digital zoom of the camera is not due to lens shift, but using a processor. If we talk about this procedure in a simplified way, then the processor cuts out the desired piece of the image and simply stretches it to the entire matrix. Obviously, with this approach, the image quality deteriorates significantly. Digital zoom is like working in the paint program, when the picture is enlarged, but at the same time its quality deteriorates so much that it is no longer possible to understand anything on it.
Advice! When choosing a camera or lens, digital zoom can be ignored, since today it is used very rarely.
Ultrazooms are a type of compact cameras that have very large optical zoom values. Currently, such devices can have a magnification of up to 60x - this is the largest zoom in a camera. One example of such a device is the Nikon Coolpix P600 model with a focal length of 4.3-258, that is, a magnification of 60x.
Conclusion
Buying a new lens is a natural step for a person who is into photography, even at a semi-professional level. When choosing it, you should not only look at the characteristics and description, but also, ideally, try how it will work on a particular camera. Given the characteristics of a particular model, the same lens can give different results with different cameras.
Aperture (aperture) - the relative opening of the lens, which allows you to adjust the flow of light entering the matrix of a digital camera and control the depth of the field of view.2. Aperture blades
The diaphragm is made up of thin metal blades that cover or open the light opening. There may be more or less depending on the lens model. The number of petals determines the shape of the diaphragm opening - it can be close to a circle, or have the shape of a hexagon. The more petals, the rounder the hole, and prettier drawing at the lens. For example, when shooting with a lens large quantity petals, even round spots are formed in the zone of non-sharpness, and not geometric figures resembling nuts. Modern lenses have rounded petals, despite their small number, provide soft and beautiful background blur.3. F-number, steps, aperture values
Aperture number is the ratio of the focal length of the lens to the diameter of the aperture, denoted as f / x, where x is it numerical value. The diaphragm controls the flow of light entering the photosensitive elements of the matrix. The larger the f-number, the smaller the transmission aperture, and vice versa, the smaller the f-number, the more hole so more light gets through. For clarity: f / 16 - closed aperture, f / 1.4 - open.Aperture values are measured in stops.
| 1.0 | 1.4 | 2 | 2.8 | 4 | 5.6 | 8 | 11 | 16 | 22 |
| 1.0 | 1.1 | 1.2 | 1.4 | 1.6 | 1.8 | 2 | 2.2 | 2.5 | 2.8 | 3.2 | 3.5 | 4 | 4.5 | 5 | 5.6 | 6.3 | 7.1 | 8 | 9 | 10 | 11 | 13 | 14 | 16 | 18 | 20 | 22 | 25 | 29 | 32 |
4. Depth of field
Depth of field (DOF) is the area in which the subject will be depicted sharply, and everything that goes beyond it is blurry.The depth of field depends on the following parameters:
- diaphragm- the smaller the aperture value (open aperture), the smaller the depth of field; at a closed aperture, the depth of field will be throughout the entire depth of the frame;
- lens focal length- the smaller the focal length of the lens (for example, wide-angle), the greater the depth of field; on long lenses, the depth of field is noticeably reduced;
- subject distance- the shorter the distance from the camera to the subject, the less depth of field, the more distance, the greater the depth of field.
As you can see from the pictures, a larger aperture gives a more blurred background.
5. The formula for calculating the depth of field
R1 - the front boundary of the sharply depicted space; R2 - rear boundary of the sharply depicted space; R is the distance in meters at which focusing is performed; f is the focal length of the lens (absolute, not equivalent), the value in meters is substituted into the formula; K is the denominator of the relative aperture of the lens (aperture number); z is the diameter of the permissible circle of confusion, for negatives of 24x36 mm format equal to 0.03-0.05 mm (the value in meters is substituted into the formula).
6. Aperture control
The primary role of the diaphragm is to control the depth of field. The aperture value is set depending on the goal. For example, when shooting landscapes, when the sharpness should be across the entire field of the frame, optimal value aperture will be f / 11 - f / 16, when shooting a portrait, where it is necessary to focus on the subject, fit value- f / 1.2 - f / 2.5, while the main subject will be in the zone of sharpness, and the background will be very blurred. When shooting at a wide aperture, certain difficulties can arise, given that the zone of sharpness is only millimeters, a small change in the angle of the camera entails a shift in focus. What to consider. Chromatic aberrations (colour distortion) can appear at a wide open aperture, while closing the aperture too much results in diffraction (loss of sharpness).7. Aperture and types of lenses
Lenses, depending on their specifications, have different minimum value diaphragm. The fastest lenses are those with a fixed focal length - aperture number from f/1.2 to f/2.8. On zoom lenses, you can often see a threshold of f values, such as 18-55 f3.5-5.6. This means that at a focal length of 18mm, the minimum aperture value will be 3.5, at 55mm - 5.6. Advantages of high-aperture lenses: high-aperture optics allow you to work in low-light conditions without using additional equipment and at low ISO; a small number of lenses in the lens design, which provides best quality Images; soft and beautiful bokeh wide open.For reference: one of the fastest lenses on the market is the Carl Zeiss Planar 50mm f/0.7, commissioned by NASA for the Apollo lunar mission. On the ground, this lens "lit up" in some of Stanley Kubrick's films.
Everyone loves to take pictures with their cell phone, but the built-in camera is different in everyone, so it's important to understand what each specification means. Then you choose a smartphone with a camera that suits your needs.
In this article, we will delve into the meanings of many features so that you can judge the capabilities of the camera by reading a description or an overview of the specifications.
Diaphragm
The aperture of a lens is the opening through which light passes to the sensor and is indicated by the numerical value F (for example, f/2.0 or F/2.8). The smaller the f-number, the larger the aperture and the more light that passes through the lens, and the better performance camera while shooting in low light conditions. The f-number you see on datasheets is the maximum possible aperture for a given focal length (more on focal length below).
For example, if a camera shoots at F/5.6, then it captures less light than at F/2.0. The 29mm f/2.2 lens on the iPhone 6 can be described as "fast", which means you can shoot at faster shutter speeds with it. The higher the aperture of the lens (the smaller the f-number), the better it is suited for shooting low-light scenes. Therefore, choose a camera that has the smallest aperture value (F / 2.2 is better than F / 2.8).
In zoom cameras like the Galaxy K Zoom and Galaxy S4 Zoom smartphones, most often you get two pairs of numbers with a focal length. At the same time, sometimes they indicate a constant aperture, but this is more typical for ordinary digital cameras and not for smartphones.
The camera in the Samsung Galaxy K Zoom is equipped with a 24-240mm f/3.1-6.4 lens. This is called variable aperture. The first aperture value (F/3.1) means the maximum aperture when shooting at the widest angle (24mm), and the second F value (F/6.4) indicates the maximum aperture opening when shooting at the tele-end (240mm). When zooming, changing the focal length, the aperture also changes.
It is also important to note that in cameras with a large sensor, the aperture value affects the depth of field. So at a large aperture, you can get a shallow depth of field, thus making a beautiful blurred background, the so-called "bokeh". Unfortunately, with a small sensor, which is found in most mobile devices, such an effect is almost impossible to obtain.
Aperture F/2.8.
As the f-stop increases to F/11, the aperture decreases and the depth of field increases, as in the example below.
Focal length
The focal length is the distance from the optical center of the lens to the image plane, in telephone cameras it means to the image sensor.
When zooming, the optical center of the zoom lens changes, so the focal length value also changes. FR also tells us about the angle of view, which is especially important. For simplicity, look at the equivalent focal length of the lens, which takes into account the size of the sensor and gives you a 35mm equivalent focal length. This figure can be compared among different cameras.
The equivalent focal length tells you how wide the lens is. You can use this converter to understand what angle of view we are talking about at a certain FR in 35mm equivalent. The shorter the focal length, the wider the field of view.
For example:
iPhone 6 / iPhone 6 Plus: 29mm (35mm equivalent)
Galaxy S5: 31 mm ( in 35 mm equivalent)
We can say that with the iPhone 6 and iPhone 6 Plus, the field of view is wider, as 29mm translates to 73.4 degrees, and 31mm translates to 69.8 degrees.
At a shorter focal length, the camera can capture more wide area scenes (vertically and horizontally). This is very convenient for shooting group shots, interiors, architecture, selfies, etc. That's why smartphone manufacturers endow the front camera lens with a shorter focal length - to make it more suitable for self-portraits.
Lenses with a fixed focal length are called "fixes". This means that there is no zoom in the camera.
Galaxy Zoom smartphones have a variable focal length. For example, the Galaxy S4 Zoom is equipped with a 24-240mm f/3.1-6.4 lens. So 24mm is the focal length at the wide end, and 240mm is the focal length at the tele-end. Of course, the aperture, as we mentioned above, is maximally open at wide-angle and minimally at the tele-end.
Video by Mike Brown.
By the way, optical zoom is calculated by dividing the maximum focal length by the shortest one. For example, in the case of the S4 Zoom, we divide 240 by 24 and get 10. In other words, the S4 Zoom has a 10x optical zoom.
Sensor size
Sensor size plays a key role in camera performance. It is generally accepted that the larger the sensor, the higher the image quality. It almost always is. For a large sensor, manufacturers can apply more technological advances that are impossible or expensive to implement in small sensors. However, among the extremely important specifications of the sensor is the size of the pixels.
Pixels are measured in micrometers (μm) or microns (μ). Some smartphone manufacturers provide this indicator because everything more people are aware of the impact of pixel size on image quality and low light performance.
The larger the pixel size (photodiode, pixel aperture), the higher its ability to collect light.
You can find two cameras that have the same size sensors but different resolutions. Here you need to decide whether you are choosing a low resolution with large pixels (like the HTC One UltraPixel) or a higher resolution with smaller pixels. Different cameras will have different sensor sizes and resolutions.
You may find a camera with large pixels that is inferior in low-light performance to another camera due to the importance of sensor technology and image processing.
For example, sensors with BSI (Back Side Illuminated) technology use unique design, significantly increasing the sensitivity to light. In the BSI sensor, the wiring responsible for data transmission is located behind the light sensitive area, which allows manufacturers to create small sensors with a large number of pixels. On FSI (Front illuminated) sensors, the wiring is in the front, taking up space that could accommodate large photodiodes.
The new generation sensors demonstrate their superiority over the earlier ones, and the sensor technology continues to improve. The HTC One UltraPixel smartphone with 2.0 micron pixels does not always result in better performance in low light compared to sensors whose pixels are smaller. The iPhone 6 Plus, with its 8MP sensor and 1.5µm pixels, is currently in first place on DxOMark. TheHTC One M8 is in 18th place, well behind even the camera in the Samsung Galaxy S5 (3rd), which has a 16-megapixel sensor with 1.12 micron pixels.
The size of the sensor, in conjunction with the characteristics of the lens, affects the depth of field. With the same aperture, a larger sensor will allow you to achieve a shallower depth of field, i.e. more pronounced bokeh. The out-of-focus background effect helps to separate the subject from the background elements.
To get a blurrier background, you need a smartphone with a large sensor and large aperture.
The size of the sensor is indicated in the specification list, it can be 1/2.3", 1/2.5", 2/3", etc. This means that this is its diagonal, but it is not easy for everyone to compare sensor sizes in this way. You can contact to the online sensor size comparison tool cameraimagesensor.com or open the Wikipedia article which lists the most popular sensor types with their equivalent width and height in millimeters.
You can see that the Nokia Lumia 1020 has a relatively very large sensor (2/3 inch = 8.80x6.60mm); Nokia Lumia 720 (1/3.6 inch = 4.00×3.00 mm).
The next time you're looking to buy a smartphone, when looking through camera specs, don't forget to look at pixel size and sensor dimensions. Most modern camera phones are equipped with BSI sensors. In some more Hi-tech than in others.
Image stabilization
Image stabilization is one of critical aspects many modern phone cameras. There is digital image stabilization and optical. With an optical stabilization system, the camera compensates for hand movement and shaking by shifting the lens elements in the opposite direction of movement, resulting in sharper images.
Images from Apple's patent application, which describes a method for integrating optical stabilization in miniature cameras.
When shooting handheld, small movements are inevitable, which can lead to a blurry picture. If you place your phone on a stable surface, this worry will disappear. Nose mobile phone most of the time you shoot handheld. In order to get a clear image, stick to the shutter speed rule of thumb, which states that the shutter speed denominator should not be less than number, indicating the focal length in 35mm equivalent. That is, to get a sharp image when shooting with a 30mm lens (equiv.), you need to set the shutter speed to 1/30 sec.
Any business begins with theory, then testing and consolidating knowledge in practice. In this article I would like to say a few words about the theory. What is a camera aperture? Where is it located, what is it and what does it affect?
So the most important thing is the definition. Aperture (from the Greek word partition) is an element of the camera lens that allows you to adjust the amount of light flux coming through the lens to the camera matrix. To put it simply, this is a hole in the lens. It is denoted, as a rule, by the letter F. In the descriptions for any lens, you can always find out its meaning. The diaphragm is one of the components of the concept.
The most important thing to understand is that a smaller number means a wider opening. And accordingly, the more the aperture of the camera is open, the more light will come through the lens. For example, f 2.8 will let in more light than f 16. It turns out that increasing the numerical value, the amount of light decreases. Here is such a simple basic essence of the diaphragm system.
An example where the shutter speed of 1/200 and ISO 200 remained unchanged, and only the aperture value changed.
On all professional cameras, the aperture priority shooting mode is indicated by the letter A. when you choose the number you need yourself, and the camera automatically .
What does camera aperture have to do with depth of field?
DOF is the depth of field depicted space or, in other words, the depth of field. Space refers to the part of the frame depicted in front of and outside the main subject. Large depth of field means that the main part of the frame will be clear and detailed. Small depth of field (depth of field), respectively, only one certain part will be in focus, everything else will be blurry.
I'll give an example: F 2.8 = open aperture = small depth of field. This scheme is great for portraits when you need to blur the background, thereby focusing on the subject, and more precisely on the eyes of the person being portrayed. We all know that the eyes are the mirror of the soul and they are the most important thing in a portrait, but more on that later.
However, a camera aperture of F 2.8 is not suitable for taking group portraits, and as a result, many faces may appear blurry. For such a case the best option you will use an aperture value of F 8 or, depending on the lighting conditions, you can set a value larger, thereby providing a greater depth of field, and the faces of people in the frame will be clear.
How does the aperture in a camera affect exposure?
Exposure is the amount of light reaching the camera's sensor in a given period of time. It is formed from three main concepts:
- diaphragm
- excerpts
All three of these combined result in a correctly exposed, underexposed (too dark) or overexposed (too bright) image.
The wider the aperture is opened (and the smaller the F value), the more light will enter and, accordingly, this will contribute to the creation of a brighter image.
Camera aperture. Where and what to apply?
There are no hard and fast rules for answering this question. However, there are guidelines that you can follow to achieve the best results for a particular genre.
For photographing landscapes or architecture, photographers often use F / 16, F / 22, which gives greater depth of field and full elaboration of details.
On the contrary, in portrait photography, small apertures of F / 2.8, F / 2, F / 1.8 are often used to focus on the model and no extraneous details will distract attention. Group portraits are best at f/8, f/11.
And finally, I will tell you: go for it! All in your hands! It may be difficult to understand at the beginning, but remember that the most The best way to understand to the end and consolidate the theory is practice. And, of course, you need to be patient in order to work everything out to the point where technical literacy will contribute to the realization of your most daring creative ideas.
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