How many megapixels are in the best camera? How many megapixels does your video surveillance need? I don't want to understand the characteristics! Which smartphone to buy with good cameras

For beginners and simple photography enthusiasts, choosing a camera is a very difficult task, because today manufacturers offer a huge variety of models that differ in both subjective parameters and technical characteristics. Moreover, manufacturing companies in advertising offers mainly emphasize the number of megapixels in their cameras.

As a result, ordinary buyers are forced to pay attention to how many megapixels are in a given camera - 7, 8, 10, 12, and so on. They are under the impression that the more megapixels, the more better camera. But is this really so? Is the number of megapixels such an important characteristic of a camera? Let's try to answer these questions.

How many megapixels do you need?

As you know, pixels are points that store information in digital form about a separate part of the frame in the photosensitive matrix of the camera. Since there are a lot of such pixels in the matrix of any digital camera, the count is already in megapixels (mega - million). So, there is a common belief that the quality of the resulting photo image depends on the number of megapixels.

In reality, the number of megapixels affects maximum size photos that you can print without loss of quality. Any digital device, be it the screen personal computer or laptop, displays the captured photo image in fixed sizes. Therefore, in order for the quality of the image displayed on the screen to be as high as possible, it must be fully consistent with the dimensions of the image captured by the camera. Otherwise, your printer or personal computer will begin to adjust the dimensions of the image to the fixed dimensions, which ultimately results in a certain loss of quality.

How many megapixels do you need in a camera in order, for example, to view captured images on a monitor screen or print images without loss of quality? It turns out that not so much. In particular, when printing standard photography size 10x15 You will need a resolution of 1180x1770 pixels, which corresponds to only two megapixels!

Of course, it is better to have a slightly higher matrix resolution, just in case, in order, for example, to enlarge or change the exposure. Thus, to print ordinary photographs for a home photo album, you will only need a camera with a 3-4 megapixel matrix. True, now such cameras are no longer on sale.

Why, in this case, do photographic equipment manufacturers focus on the number of megapixels and constantly release new models of cameras with higher matrix resolution? First of all, this is a good marketing move. After all, it’s always nice to brag to your friends or acquaintances that you have a 12-megapixel camera, while they are the owners of “some” camera with a 7.1-megapixel matrix.

But there is still a practical benefit from a large number of megapixels. True, it only appears when you are going to print photos in large format - large posters or posters. If you are engaged in professional studio photography and often print large photographs, then here you can choose a camera with a matrix of 10 - 12 megapixels. So, the more megapixels in the camera, the fewer restrictions on the size of a high-quality photo. The quality of photographs is influenced by completely different parameters.

The physical size of the camera matrix.

The quality of the resulting images is influenced by a completely different characteristic than the number of megapixels in the camera matrix. This is, first of all, the physical size of the camera matrix. The physical size of the matrix refers to the geometric dimensions of the sensor, that is, its length and width in millimeters.

True, in the description technical characteristics In cameras, the physical size of the matrix is ​​most often indicated in the form of fractional parts of an inch, for example, 1/2.3″ or 1/3.2″. The larger the matrix, the smaller the number after the fraction. The value of 1/2.5″ corresponds to the geometric dimensions of the sensor - 4.3x5.8 mm.

What is affected by the physical dimensions of the camera matrix? This parameter determines the level of digital “noise” and the detail of the photographic image. The larger the size of the photosensitive sensor, the larger its area and, accordingly, the more light hits it. This allows you to get a high-quality image with more detail and natural colors.

Since the physical dimensions of the matrix in compact cameras are smaller than in more professional camera models, they are inferior in terms of the quality of the resulting images. Therefore, if you are choosing the best camera option from several models with the same number of megapixels, then it is better to choose a digital camera with a larger physical matrix size. This will give you greater freedom when choosing where to shoot and will reduce the level of “noise” in low light conditions.

You should never focus your attention on the number of megapixels in a camera. Manufacturers of photographic equipment use this characteristic, first of all, as an advertising technique to promote their new models on the market. Most users who are simply going to store their pictures in electronic format and show them to friends from time to time in a home photo album may well limit themselves to buying a camera with a minimum number of megapixels, because they still won’t feel the difference between a 7 and 12 megapixel camera.

From the point of view of the quality of the resulting photographic images, another parameter is much more important - the physical size of the camera matrix. This characteristic, as well as the quality of optics and functionality, is what you need to focus on when choosing the right camera for you.

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It is noteworthy that even a slight increase in linear resolution is accompanied by a significant increase in the number of megapixels. This is similar to calculating area. To double the number of megapixels, it is enough to increase the linear resolution by 41%, and doubling the linear resolution leads to a fourfold increase in the number of megapixels. It is for this insidious property that megapixels are so dearly loved by marketers, since it allows them to present very moderate progress as something revolutionary.

In fact, a twofold increase in the number of megapixels is not a revolution at all, it is just the minimum after which the increase in detail becomes noticeable for most people, and only if the detail was limited solely by the number of pixels, and not at all by lens aberrations or misses focusing, camera vibration and poor editing. Moreover, the contribution of the matrix resolution to the overall sharpness of the image rapidly decreases as the number of megapixels increases. Up to 10 megapixels, this contribution is very significant, from 10 to 20 megapixels it is no longer so significant, and with a resolution above 20 megapixels, the quality of the optics and the skill of the photographer unconditionally come to the fore.

Is excess megapixels harmful?

In general - no, it is not harmful. I just consider it necessary to emphasize that there is not much benefit from it. In my opinion, the only truly negative effect associated with an increase in resolution is a proportional increase in the volume of files, which rapidly fills memory cards, devours disk space and slows down the computer during post-processing.

It may be objected that cameras with higher resolutions are also noisier at high ISO values. This is true, but only when comparing images pixel by pixel, i.e. at 100% magnification. With an equal scale, the noise level will be approximately the same (other things being equal, of course). For example, if a picture taken with a 36-megapixel camera is reduced to 16 megapixels in Photoshop, then in terms of noise level it will practically not differ from a similar picture originally taken with a 16-megapixel camera. In this case, the reduced image may even look somewhat sharper, since reducing the image (decimation) to a certain extent neutralizes the loss of sharpness that is inevitable with Bayer interpolation.

Thus, high resolution actually allows the camera sensor to collect more information about the scene being photographed and potentially provide better detail in the photo. Another question is, will you be able to take advantage of this potential, or will it only translate into extra gigabytes occupying your hard drive?

To understand what number of megapixels will be necessary and sufficient for you, you just need to remember what end use you find for your photos? Do you view them on a computer monitor or perhaps using a digital projector? Do you print your own pictures, and if so, what is the maximum print size? Do you share your pictures online? Do you subject your pictures to any processing, or are you content with what comes out of the camera?

Viewing photos on a computer monitor

The most common screen resolution among visitors to my site is 1920x1080 (Full HD), which roughly corresponds to two megapixels. For laptops, the most popular resolution is 1366x768 (WXGA), i.e. one megapixel. Rare visitors use monitors with a resolution of 2560×1440 (WQXGA), which is less than four megapixels. iMac computers with Retina displays is so small that they can be neglected.

The conclusion, it seems to me, is obvious: in most cases, 2-4 megapixels is enough to view photos on a personal computer monitor. And this is if the picture is expanded to full screen, and not huddled in a small window.

Projectors

Mass models of modern digital projectors have a resolution of 1920x1080 (Full HD) or even less, which means trying to demonstrate to the public anything more than a couple of megapixels with their help is pointless. Projectors with a resolution of 4096x2160 (4K) are simply not affordable for most photographers, but even less than nine megapixels is not that much by modern standards.

Printing photos

The resolution of a print, regardless of its size, is usually measured in dots per inch (dpi). For example, when printing at 300 dpi, there will be 300 dots per linear inch (2.54 cm), which corresponds to 118 dots per linear centimeter.

A resolution of less than 150 dpi is considered low, from 150 to 300 dpi is acceptable, and from 300 dpi and more is high. High resolution means that the individual points that make up the image are virtually indistinguishable to naked eye. Typically, moderate-sized prints (up to A3 inclusive) are made with a resolution of exactly 300 dpi. For larger prints it is acceptable to use a lower resolution.

Much depends on the distance from which you are going to view the photo. Small cards are viewed closely and their resolution should be as high as possible. Large canvases are hung on the wall and admired while standing at some distance, and therefore even a relatively low resolution will not hurt the eye. This also applies to photo wallpapers. Huge billboards that people look at from tens of meters away can be printed at 32 dpi and they will still look good.

The table below shows how many megapixels are required to take and then print photographs at both 150 and 300 dpi resolution at various print sizes.

When was the last time you printed your photos on A3? Let me remind you that the most popular print size among amateur photographers is A6, i.e. 10×15 cm.

Internet

The Internet doesn't like big photos. Firstly, large photos take a long time to load, and secondly, most people are simply not interested in looking at the microscopic details of other people's photos. The only exception is specialized photographic forums. As for social networks, your multi-megapixel images will in any case be reduced when uploaded to the server, regardless of your consent, and the quality of decimation will not be the highest.

If you send photos to relatives and friends via email, then it is necessary to reduce them at least for reasons of basic decency. Who wants to wait for huge files with flowers and kittens to download?

In a word, here, too, literally a couple of megapixels will be enough for you.

Of course, all this applies exclusively to amateur photography and does not apply to images intended for commercial use. It all depends on the specific situation. If the customer demands 20 megapixels at all costs – so what? – we’ll send him exactly 20 megapixels, but whether he really needs them is no longer our concern.

Image processing

When editing photos in Adobe Photoshop or other graphic editor some excess resolution is not only tolerable, but highly desirable. Firstly, many SIM cards need cropping, i.e. in trimming edges, and it’s good when you have the opportunity not to save pixels. Secondly, competent image reduction - best way hide or at least minimize image defects such as noise, chromatic aberrations, moderate motion, interpolation artifacts, etc. In other words, a photo taken at high resolution and then downsized almost always looks better than one originally taken at low resolution.

However, it should be noted that the resolution of modern cameras is so high that there is almost always a supply of megapixels that can be sacrificed when editing.

Conclusion

You and I have talked for too long about something that shouldn’t be talked about at all. Let us finally sum up the results.

To satisfy the needs of the vast majority of amateur photographers, ten megapixels will be enough, although even this number seems somewhat excessive. It's rare that an enthusiast will be able to fully realize the potential of twenty megapixels, but such people usually know what they want. Those photographers who may objectively need higher resolution, and who know how to handle it, are unlikely to read this article.

Considering the fact that the resolution of more or less serious cameras today averages about two dozen megapixels and continues to grow, I consider further discussions on this topic simply unnecessary. The number of megapixels is no longer a parameter that you should seriously consider when choosing a camera.

Thank you for your attention!

Vasily A.

Post scriptum

If you found the article useful and informative, you can kindly support the project by making a contribution to its development. If you didn’t like the article, but you have thoughts on how to make it better, your criticism will be accepted with no less gratitude.

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The term "megapixel" can be deciphered as one million pixels. That is, a 12-megapixel camera takes pictures that consist of 12 million tiny dots. The more these dots (pixels) in the image, the sharper it looks, the higher its resolution.

From this we can conclude that a camera with a large number of megapixels shoots better than that one, which has fewer of them. But this is not entirely true.

The problem is that nowadays they have more megapixels than they need. Let's remember about screens: a FullHD TV has a resolution of 2.1 megapixels, and the latest 4K TV has 8.3 megapixels. Considering that almost everyone is in the cell modern smartphone You can count more than 10 megapixels; displays simply cannot display such a high resolution to the fullest.

It is unlikely that you will notice the difference between photographs of modern cameras with different numbers of megapixels, since even latest screens do not support such permissions.

In fact, going over the 8.3 megapixel mark can be useful if you intend to crop your shots. In other words, if you take a photo with a 12-megapixel camera, you can cut off a significant portion of it. However, the image resolution may still remain higher than that of a 4K TV.

Advice. Don't go for cameras that have more than 12 megapixels. This amount is enough to spare, unless you are going to cut the pictures into fragments or edit them for professional purposes.

Pixel size is more important

An indicator that more accurately characterizes a smartphone camera is the pixel size. In the general list of characteristics, its numerical value is indicated in micrometers before the abbreviation µm. A smartphone camera with a pixel size of 1.4µm almost always takes better pictures than another with a pixel size of 1.0µm.

If you zoom in close enough to a photo, you can see individual pixels. The colors of these small dots are detected by microscopic light sensors inside the smartphone's camera.

These sensors are also called pixels because each sensor captures light for a corresponding pixel in the image. So if your camera has 12 megapixels, it has 12 million light-sensitive pixels.

Each sensor captures particles of light known as photons and uses them to determine the color and brightness of a pixel in an image. But photons are very active, and capturing them is not so easy. For example, instead of a blue particle, the sensor can catch a red one. As a result, instead of a pixel of one color, there will be a dot of another color in the image.

To avoid such inaccuracies, a light-sensitive pixel catches several photons at once, and special software uses them to calculate the correct hue and brightness of the point in the final photo. How larger area pixel, the more photons it can capture, the more accurate the colors in the final image.

Advice. Stick to cameras that have no more than 12 megapixels. A larger number forces the manufacturer to sacrifice pixel size in order to fit everything into a limited space. When comparing cameras with the same number of megapixels, choose the one with larger pixels.

Aperture

Other important characteristic A camera that should not be neglected is the aperture. It is indicated using the symbol f divided by the numeric value. For example: f/2.0. Since f is divided by a number, the smaller it is, the better the aperture.

To understand the meaning of aperture, think about pixel size. The larger it is, the more particles of light the camera captures, the more accurate the color rendition. Now imagine that the pixel is a bucket and the photons are raindrops. It turns out that the wider the bucket (pixel), the more drops (photons) fall into it.

The aperture resembles a funnel for this bucket. Its lower part is the same diameter as the bucket, but the upper part is much wider, which helps to collect even more drops. As the analogy suggests, a wide aperture allows the sensor to capture more light particles.

Of course, in reality there is no funnel. This effect is achieved through a lens that allows the camera to capture more light than its pixels can capture.

The main advantage of a wide aperture is that it makes the camera better at shooting in low light conditions.

When there is too little light, the light-sensitive pixels may not capture enough photons. But a wide aperture solves this problem by allowing access to more particles.

Advice. Remember, a lower number means a wider aperture. So opt for cameras with f/2.2 or lower, especially if you often take photographs at night or indoors.

Image stabilization: EIS and OIS

Among other camera characteristics, you can find two types of image stabilization: optical - OIS (Optical Image Stabilization) and electronic - EIS (Electronic Image Stabilization).

When the camera sensor moves due to hand shake, OIS physically stabilizes the image. If you walk while shooting video, for example, each step usually changes the camera's position. But OIS keeps the sensor relatively stable, even if you shake your smartphone. As a result, the technology minimizes judder in videos and blur in pictures.

The presence of optical stabilization greatly increases the cost of the device and requires a lot of space for additional parts. Therefore, instead of it, electronic stabilization is often introduced into smartphones, which creates a similar effect.

EIS crops, stretches, and changes the perspective of the individual frames that make up a video. This happens in software and with the footage, so electronic stabilization can be applied even to videos recorded on cameras with OIS to make them even smoother.

By and large, having a camera with optical stabilization is better. After all, electronic processing of frames can reduce the quality and create a jelly effect on the video. In addition, EIS almost does not reduce the degree of blur in images. But it is worth noting that electronic stabilization does not cease to develop, which confirms the quality of videos shot on devices.

Advice. If you can, choose devices with optical stabilization; if not, stick with electronic stabilization. Ignore devices that do not support either OIS or EIS.

The race for megapixels from digital photography has gradually moved into IP video surveillance. Our clients are increasingly asking for cameras of 3, 4, 5 megapixels and even higher. Most of them are absolutely sure that the higher the resolution, the more megapixels the camera has, the better it will show, the higher the detail of the frame will be. Manufacturers, to please consumers, produce high-resolution cameras; 12 MP IP cameras, in the now fashionable 4K format, are already being sold with all their might.

We decided to figure it out - does the video quality of IP cameras really increase with increasing megapixels? Is it worth overpaying for high-resolution cameras, NVR processing power, high throughput networks and for terabytes disk space necessary for this high resolution. We selected several cameras from stock with different resolutions - from 1 to 5 megapixels. We also ordered several expensive 5 - 8 MP IP cameras from manufacturers for this test. This is who came to us for testing.

We gave preference to outdoor IP cameras with a fixed lens, because... they do not need to be adjusted, and errors in the tedious adjustment of varifocal lenses will not affect the quality of the video image. True, we did not find 5-megapixel cameras with a fixed lens and tested 5MP varifocal cameras. We installed all the cameras in the same place and pointed them at the opposite wall, where we have several homemade “test tables” hanging.

Let's see what we got. All frame shots were taken through web interface cameras using the IE browser and the ability to save a still image built into each camera. In the table below we have placed a reduced frame to a resolution of 640x480 (or 640 by 360 if the camera has a widescreen matrix with an aspect ratio of 16:9), as well as a crop (cut out of the frame) with a resolution of 200x360 pixels. It more clearly shows the quality of the “drawing” of small details of the image - in particular, the letters on the Sivtsev table (a table for testing vision).

To view a full-size frame from an IP camera, click on its small copy in the table.

What we noticed when comparing these frames:

1. Cameras have different aspect ratios. IP cameras with a resolution of 1, 2, 4 megapixels have a widescreen frame with a 16:9 ratio. And cameras with a resolution of 1.3, 3 and 5 megapixels are 4:3. Those. the latter have a greater vertical viewing angle. This is very important for those cameras that will “look” at an object from top to bottom. For such cameras, there will be fewer dead spots under the camera both near and far. It is interesting to note that a 3MP camera compared to a 4MP camera not only has a larger vertical viewing angle, but also a resolution: 1536 versus 1440 pixels.
2. Cameras have different viewing angles, and it depends not only on the lens, but also on the size of the matrix. Budget IP cameras with a 1/4 matrix and a standard 3.6mm lens have a horizontal viewing angle of no more than 60°. But the 5MP IPEYE camera with a 1/2.5 matrix has a wide viewing angle both vertically and horizontally (more than 110°). It’s true that the lens at its shortest focus has a distance of 2.8mm.
3. Well, the most important thing we wanted to pay close attention to is the resolution. If you look closely at all the frames, you will notice that, undoubtedly, as the resolution (megapixels) increases, the detail increases. But NOT PROPORTIONAL! Not huge. A 4MP camera does not improve the image by 2 times compared to a 2MP camera. Detail increases slightly. In any case, not a single camera could “cope” with the second line from the bottom of Sivtsev’s table. And already the 6th bottom line (right letters “B K Y”) is confidently “read” by both cameras with a resolution of 4 and 2 MP.

Of course, here we need to make allowances for different viewing angles. After all, as the viewing angle increases, we seem to move away from the scene being filmed and the detail deteriorates. This is especially true for the 5-megapixel IPEYE camera - the viewing angle provided by this combination of matrix and lens is too wide. And if you make the angle on it the same as that of 2MP cameras (about 90°), then the letters of this table will be read more confidently.

Interestingly, another 5MP IP camera with the same declared parameters (2.8-11 lens, 1/2.5 matrix) has a slightly narrower viewing angle at the shortest focal length than the IPEYE-3802VP. Detail is approximately at the same level, the picture is somewhat noisier in dark areas of the frame, although the cost of the BEWARD camera is several times higher. But it has a motorized lens and you can control the viewing angle while sitting in front of the computer. A picture with a maximum focus of 11 mm will then look like this:

Maybe someone needs this, considering that every time you change the focus of the lens, you need to either manually or by pressing the “autofocus” button to adjust the sharpness of the image. And this takes from 5 to 20 seconds. But here you can confidently read the second line from the bottom of the vision test table.

Subsequently, we tested a pair of 2-megapixel IP cameras with a 2.8 - 12mm varifocal lens, because... There is an opinion that they show better than “fixes”. Here's what we got:

As you can see, the result is not much different from the previous one. The detail is almost the same as that of 2MP IP cameras with a fixed lens. Even the expensive 2 megapixel (!) Hikvision camera (the retail price of which as of February 2016 was 21,990 rubles) with a viewing angle of 50 degrees set at the factory (and to change it, you had to open the camera, which we absolutely did not want) The readability of Sivtsev’s table was no higher than 5th line from the bottom.

Perhaps varifocal lenses have greater photosensitivity and IP cameras with them can “see” better in the dark, but this is the topic of a completely different test and another article, which we may turn to later. But varifocal lenses have virtually no effect on resolution. Moreover, the slightest inaccuracy in focusing settings can lead to disastrous results, and all megapixels will be useless. And anyone who has ever set up a varifocal lens on an IP camera will agree with me that this is oh so difficult, given the delay with which the signal from the camera arrives at the monitor.

This is the first camera with a 1/1.8 sensor size that we got our hands on. In addition, this camera is capable of delivering a stream at a speed of 25 fps with a 5-megapixel resolution (2592x1920 px). Others cannot do this yet. The maximum they are capable of is 12-15 fps at maximum resolution. What immediately catches your eye is the wide viewing angle of this camera. With a focus of 3.6 mm, it is wider than 5MP cameras with a 1/2.5 matrix with a focus of 2.8 mm. The resolution of the camera from BSP Security is at the level of other 5-megapixel cameras, even a little clearer. At least the contrast of the picture is higher. However, the situation is slightly overshadowed by blurring of the left side of the frame. Perhaps we were unlucky and came across a camera with a slight distortion of the matrix.

And finally, 4K IP cameras with 8MP resolution arrived at our warehouse. This is a hemisphere with a fixed lens DAHUA DH-IPC-HDW-4830EMP-AS. Here's a shot from that camera:

To open a frame full resolution, in the browser, right-click on the picture and select the “open image” menu item.

We didn't stop our test with office pictures; we also wanted to look at real footage of a street scene. To do this, we pointed our camera lenses at the nearest parking lot, visible from our window. We did this deliberately in rather difficult light conditions - early twilight. This is what we got.

Perhaps we chose a part of the day that was still too bright (17.10 - 18.00 in February), but all the cameras did an excellent job with such lighting. True, the 1.3 MP camera MT-CW960IP20 had a slightly darker picture than others, which is quite strange, because... the 1/3 matrix should have better light sensitivity compared to the 1/4 matrix.

As for the detail of the picture, the situation is similar to the results of testing in the office. Although it increases with increasing megapixels, it is not significant. Both 4 and 2 megapixel cameras were able to read Renault's license plate number. True last ones A little worse.

IP cameras with a resolution of 1.3, 4 and 5 megapixels with their wide viewing angles even “saw” the license plate of our van in which we carry all these IP cameras)). And the 5 MP camera even saw a car standing to the left of the van. The viewing angle is amazing!

In March, we received two more 5-megapixel IP cameras BEWARD and BSP Security for testing. Let's compare how they show on the street.

5 MP IP camera: resolution 2592x1944, matrix 1/2.5, zoom lens 2.8 - 11 mm
5 MP IP camera: BSP Security, resolution 2592*1920, matrix 1/1.8, lens 3.6 - 11 mm

The cameras were tested at the same time (18.00 in mid-March). It is interesting to note that despite the fact that the camera from BSP Security has a wider angle, it has slightly better detail. State The license plate on the blue Ford can almost be read, which is not the case in the BEWARD camera footage. The matrix size has an effect - 1/1.8 versus 1/2.5.

What conclusion can we draw?

1. The treacherous pursuit of megapixels is practically useless and only plays into the hands of manufacturers (well, let’s be honest - we, the sellers of these IP cameras, recorders and hard drives) they make more profit.
2. In the vast majority of cases, 1- and 2-megapixel IP cameras are sufficient. And if you need better detail of distant objects, then this problem should be solved not by mindlessly increasing megapixels, but by reducing the viewing angle using a varifocal lens. With this we will “bring the picture closer” to ourselves and will be able to see everything we need. And an increase in the number of video cameras. This solution may be a little more expensive, but it will definitely solve your problem. And perhaps the price of a pair of 2-megapixel cameras with a viewing angle of 50° (for example, “fixes” with a 6mm lens) will be less than the price of one 5- or even 4-megapixel with a viewing angle of 100°. But they will give us much more information about the observed territory.
3. It should be taken into account that increasing the number of pixels without increasing the physical size of the matrix only worsens the sensitivity of the video camera, because The pixel area becomes smaller and less light reaches its surface.
4. Real high-quality lenses with optics that allow you to get all the advantages of multi-megapixel matrices cost at least $1000. What can you expect from a 12-megapixel camera worth 20,000 rubles?
5. Well, the last thing to remember is that with an increase in “megapixel” you will additionally overpay for the processing power of the devices being recorded, storage devices (HDD), network bandwidth and traffic when viewing via the Internet.

P.S. We will continue to test IP cameras that come into our hands in this way. Several test samples have already been requested from various suppliers with resolutions ranging from 5 to 12 megapixels. Therefore, please visit this page periodically to receive new information about the megapixel race in IP video surveillance.

P.P.S. If any of the manufacturers or suppliers would like to test their cameras on our “test bench” - welcome, contact us by e-mail: kb063_sobaka_yandex.ru

The resolution of a digital device’s matrix is ​​usually measured in megapixels. If your smartphone camera has more megapixels than your camera, does that mean it's better? Not at all.

Just like calories, megapixels represent quantity, not quality. The number of calories in a dish is not an indicator of its nutritional value, just as the number of pixels in a camera does not indicate the quality of the pictures taken with its help.

The quality of a photograph depends on a number of aspects, such as optics, light, image sensor characteristics, firmware and pixels, but in this case We are not talking about the number of megapixels.

The image in the camera is formed on a photosensitive element - the matrix. After passing through the lens, the light is focused onto the camera's image sensor. The sensor consists of photocells, each of which corresponds to an image element, that is, a pixel. Each pixel in the image sensor records the amount of light that hits it and converts it into a corresponding number of photons.

Image sensors can come in different sizes. The larger the sensor, the larger the pixels and, therefore, the more light they can collect. The result is a cleaner picture, with less noise and generally better differentiation between highlights and shadows.

Lens diameter gives you a rough idea of ​​the size of your camera's image sensor. 8 megapixel sensor iPhone cameras is the size of a small aspirin tablet, but a compact camera with the same number of megapixels has a larger sensor and, accordingly, a larger pixel size. The larger the physical size of the pixel, the more light will fall on it and the less noise will affect it.

This was the case before, but now the situation is beginning to change. With the advent of more modern smartphone models such as the iPhone 7 and Samsung Galaxy S7 Edge, the pixel size (µm) in device sensors has increased (up to 1.2 microns in iPhone and up to 1.4 microns in Samsung), which puts them almost on the same level as sensors in cameras (not all, of course).

Advanced compact cameras, mirrorless cameras, semi-professional and professional digital SLRs have large image sensors, the sizes of which range from the size of a postage stamp (APS) to full-frame sensors.

Sensor size comparison

When are there too many megapixels?

In some cases, a large number of pixels can affect the quality of the photo. For example, if you post an image that is too large to social network or send it for printing, the photo size will be automatically reduced with loss of quality. Uploading large size images requires more time and the process will not always be completed successfully. In addition, files that are too large take up a lot of space free space on disk.

In modern cameras, the megapixel count has already exceeded ten, but traditional digital cameras, just like camera apps on smartphones, allow you to lower the resolution if desired. In addition, using free photo editors (even with basic functionality) you can reduce the resolution of a photo before publishing it on a social network or before printing.

What is DPI?

DPI (“Dots Per Inch”) is a frequently encountered abbreviation that translates from English as “dots (pixels) per inch” (2.541 cm) and denotes the resolution of an image.

How many megapixels are required to print high-quality photographs on paper?

High quality photography (and those same megapixels) is important in cases where the image needs to be printed or made into a photo album. You can calculate what size the pictures should be in order to get the highest quality photo possible as follows. First, determine the physical size of the photo in inches (20 x 25 cm = 8 x 10 inches, 10 x 15 cm = 4 x 6 inches, etc.), then multiply the width and height by 300 DPI (optimal resolution). This will give you the size in pixels. That is, a photograph in the format 20 × 25 cm = 8 × 10 inches = 2,400 × 3,000 pixels (7.5 million pixels). Then divide this result by 1,000,000 to get the number of megapixels needed for a quality print. IN in this example The minimum camera resolution must be 7.2 megapixels.