What are megapixels and what are they for?

Pixel is light-sensitive cell located on the lens matrix and forming an image. Each of them consists of five elements of information: three are responsible for determining the color (brightness of red, blue and green), two more are for coordinates (vertical and horizontal position). Together they allow the reader to determine the correct dot color and place it in the correct location on the screen. Pixel is that very tiny square, the "grid" of which you see on the screen when the image is greatly enlarged. Together, the pixels form the finished image.

In this case, the prefix "mega" means million, that is, megapixel is value of 1 million pixels. In MP, the resolution of the matrix and the size (but not the quality) of the photo are measured. Sufficient number of megapixels affects the detail and increases the resolution of the image. High resolution is relevant for large format printing, where the number of megapixels affects print quality. But you must admit, it is unlikely that anyone will print billboards from a smartphone, and for the usual viewing of personal archive on the screen of phone, tablet or computer, few megapixels will be enough for you. If you want quality shot, and not just an image that won't be "grainy" when zoomed in, there are other factors to consider.

Size matters

Unfortunately, the number of megapixels is present in every smartphone advertisement, but manufacturers often keep silent about more important indicator - pixel size. This indicator is measured in microns (or μm in Latin). The larger the pixel size, the more photons it absorbs during the exposure of the frame. Simply put, larger pixels capture more light, reduce image noise, and provide greater detail. In good lighting, the difference may be less noticeable, but in poor lighting, camera with “modest” 12 MP, but large pixels, will produce better photos than 20-megapixel camera with smaller pixels. Therefore, remember an important rule: it is better to have few megapixels with large dots than many with small dots.

Why, then, smartphone manufacturers do not follow this rule? It's simple: pixel sizes directly affect the size of the matrix, large sensor requires large-scale optics, and this is reflected in the thickness and width of the smartphone itself. Spoiled users are accustomed to thin and light gadgets, and few people like bulging camera. Therefore, often the size of the matrix is sacrificed for the sake of comfortable and attractive case.

Sensor size is expressed in fractions of an inch and is expressed as fraction of 1/x—for example, 1/1.7. And the smaller the number "x", the better the sensor. Since 2022, trend has begun for inch photomatrices, that is, huge (by the standards of smartphone) matrices with diagonal of 1 inch. They are capable of accommodating larger pixels and capturing more light, thereby improving the quality of shooting in low light conditions. This figure is already close to what compact "soap dishes" and even SLR cameras offer. Smartphones such as Sony Xperia Pro-I, Xiaomi 12S Ultra, Xiaomi 13 Pro, Vivo X90 Pro Plus, etc. can boast of having an inch sensor.

Xiaomi 13 Pro smartphone with 1-inch camera sensor.

What is binning

In order not to increase the size of the matrix, manufacturers have come up with such trick as binning technology. It is the combination of neighboring camera pixels to increase sensitivity in exchange for decrease in resolution. You can combine 4, 9, 16 or more pixels at the same time, combining them into one large light-sensitive pixel. As result, photos are more detailed in low light conditions. But their real resolution is several times less than those same marketing 108 or 200 MP. For example, 64 MP camera produces 16 MP images, as it uses the combination of four pixels into one. On cameras with small (or rather, sufficient) number of megapixels, this technology is usually not used, since it is simply not necessary. In this case, binning is implemented using not hardware, but software, that is, special algorithms.

Binning technology involves combining neighboring pixels.

Diaphragm

But even smartphones with an inch sensor and binning technology cannot always become the best camera phones and provide the user with professional shooting quality. After all, it also depends on other factors. And one of the important indicators is the size of the aperture, which is also called aperture or aperture. In the simplest terms, this is small hole in the lens through which light enters the device. Fortunately, unlike the size of the pixels and the photomatrix, this indicator of the company is almost always indicated in the specifications. The larger the aperture, the greater the “openness” of the lens, which means it will be able to let in more light. The more light the lens lets through, the brighter and more detailed the photos will be. By the way, here it is worth remembering the size of the matrix, because the larger it is, the larger the aperture size should be. If it doesn't let enough light through, even the giant sensor will be useless. Therefore, when choosing smartphone, you should definitely not skip this item.

Aperture size is indicated by the letter f followed by fraction. The smaller this figure, the greater the aperture ratio. For example, f/1.8, f/1.7, f/1.6 are optimal for bright, detailed photos, while settings like f/2.2 and f/2.0 will result in poorer, blurry shots.

The larger the aperture, the more light it will absorb.

Soft

Even if you take two different smartphones with identical camera characteristics, most likely they will shoot differently. After all, photo processing, for which the software part is responsible, is of great importance. And this is not about the interface of the camera application or filters that can be “imposed” for beautiful Instagram selfie, but about working algorithms that unlock the potential of the technical part. Even good equipment with "raw" software support will produce mediocre shots. And vice versa, not the top-end sensor will become worthy competitor paired with good software. An important role is played by the image processor.

It is because of this that iPhones are considered one of the best camera phones, and smartphones from other manufacturers, even with large sensors and an impressive number of megapixels, often cannot reach their level. Google isn't in the megapixel race either, but its smartphones typically perform much better than competitors in the same price range or even higher.

Special attention should be paid to artificial intelligence, which is currently used in many smartphones. Having learned from huge number of shots, AI can safely be called professional who will help you choose the optimal settings for color, contrast, depth, etc. And since most users do not want to deal with numerous nuances and go into the wilds of manual settings (many do not even try it do or are not even aware of the presence of settings), artificial intelligence becomes very useful addition. And here it is also important how it was set up initially: sometimes the AI tries too hard, and when viewing photo, there is desire to take new frame or “roll back” the picture to the original version. Unfortunately, the software part cannot be translated into numbers and exact characteristics, so you can evaluate it only when using the camera directly.

What else to pay attention to

Optical stabilization(aka OIS) is so-called shock absorber (actually special movable lens block) that makes photos and videos clearer, even in spite of movement and camera shake. It will come in handy if you are, for example, photographing landmarks while driving by, or filming roller coaster ride. Yes, shaking may already be present from the hands. With OIS, this will not turn out to be blurry spots, but quite clear frames. Roughly speaking, optical stabilization is kind of alternative to tripod and is especially relevant when shooting video on the move. It is mainly inherent in more expensive models. Cheap solution is electronic stabilization, which does not require special equipment - only software algorithms. It is used in low-cost devices, but it is, of course, not as effective as optical stabilization. And relatively recently, manufacturers have begun using sensor-shift stabilization. In this case, the stabilization mechanism is located not in the lens, but directly on the matrix. It is able to dampen camera vibrations in five directions: up/down and to the sides, linear shifts and rotation around the optical axis.


Zoom. In simple terms, this is an increase or approximation of an object - for example, house located block away from you, shooting star in the sky, or balcony on the 6th floor of high-rise building. The simplest type is digital zoom, which simply crops the necessary fragment, stretches it to the entire frame, and thereby degrades the quality of the image. Optical zoom takes different approach by changing the focal length of the camera. As a result, the pictures are clearer and more detailed. Most often, optical zoom is provided by special camera module - telephoto lens. There's also hybrid zoom that combines optical zoom, digital zoom, and software to improve results. For example, the Samsung Galaxy S23 Ultra has 100x hybrid zoom capability and dedicated Space Zoom mode for detailed photos of the moon and more.

The Samsung Galaxy S23 Ultra has 100x hybrid zoom.

Why does smartphone need multiple cameras?

To date, smartphones with just one main camera module have become endangered dinosaurs, because even state employees are equipped with at least two sensors. Of course, there are situations when their number is just another marketing ploy, but often additional modules play an important role and significantly improve the quality of filming. All cameras have main sensor, which usually has the most megapixels and is versatile. Simply put, he can shoot on his own, but additional lenses cope with specific tasks much better. So, a telephoto lens has large focal length and better captures distant objects, that is, it is responsible for the zoom. An ultra-wide lens will help capture large buildings, panoramas and large groups of people - that is, something that does not “fit” into the camera during normal shooting. A macro lens comes into play when you need to photograph very small object from distance of few centimeters or even less - for example, an insect, drop of water, etc. In addition, there may be auxiliary lenses that do not work on their own, but help the main camera. For example, few years ago, TOF (Time of Flight) sensors were very popular. They are able to determine the time for which the light reflected from the object returns to it. Thanks to this, TOF sensors accurately calculate the distance to objects and determine their shape. Thus, camera add-ons are important, but only if they really work well and are added for quality result, and not just for list of features.


To sum up, smartphone camera (like other gadgets) is complex mechanism, and not just number of megapixels. Without good optics, the correct size of the matrix, well-developed algorithms and software refinement, these numbers mean nothing. That is why, according to the results of testing by DxOMark experts , the Huawei P60 Pro with 48 MP lens received the maximum (at the time of writing) 156 points, and the Samsung Galaxy S23 Ultra with 200 MP is ranked lower than the Google Pixel 7 Pro with 50 MP main sensor and even Apple iPhone 13 Pro with three 12 MP lenses. So if you choose camera phone, when choosing, pay attention not to the number of megapixels, but to the real capabilities of the camera. To do this, read the reviews and reviews, and if possible, test the gadget personally. Our site has filters for easy search: camera phones, smartphones with a good camera, TOP DxOMark, etc.