Cameras of modern smartphones are getting better every year. At the same time, the difference between them is being erased more and more. Previously, it was possible to roughly judge the quality of a mobile camera by the number of megapixels. Today this characteristic is far from the main indicator. Even more confused by the fashion for two, three, four or five cameras in the phone. More cameras means better shooting? Not really. How not to get confused in choosing a modern camera phone, we will tell you in this article.
For a long time, mobile phones showed an almost direct dependence of the quality of the camera on its resolution. The more megapixels, the better the quality was. Large resolution modules were larger and more expensive than “smaller” ones, and were installed only in flagships. Resolution grew every year – after 2 megapixels there were 3, then 5, then 8 … The decline of the “race of megapixels” began with the Sony Ericsson Satio, the first smartphone with a 12 megapixel camera. A further increase in sensors did not significantly affect the quality of the photo. Rather, it was related to the testing of new technologies and marketing.
Sensors of this resolution are used in many smartphones even now, even in top-end ones – take at least the Galaxy S21 or iPhone 13. But modern flagships shoot much better than the models of previous years. And much better “budget” like Redmi Note 10 Pro. Although the latter has a camera of as much as 108 megapixels. It turns out that happiness is not in megapixels? Partly yes. Then what, in the number of cameras? Or something else? To figure it out, let’s take a look at each item separately.
Resolution is one of the main characteristics of an image sensor. Modules of the main cameras in modern smartphones have a resolution of 12 to 108 megapixels. This is not the limit: there are already 200 megapixel cameras on the way.
However, this characteristic itself has little effect on the image quality. It works only in conjunction with others. An important role is played by the matrix and pixel sizes, lens aperture, and software processing. But high resolution still gives some bonuses. For example, the zoom of a certain area of the frame will turn out to be of higher quality than in a camera with a low resolution.
One of the main characteristics that affect the quality of photo and video shooting. The larger the matrix, the more it captures light. This means that the better and more detailed the photos and videos are. The size of the matrix is counted in fractions of an inch. The characteristic is represented as an expression 1 / x. The lower the number divided by the inch, the larger the camera matrix. For example, the diagonal of a 1/3 inch matrix is 5.8 mm, a 1 / 2.3 matrix is 7.8 mm. Modern flagships are equipped with the largest matrices, up to 1 / 1.28 inches – the diagonal of such a matrix is almost 20 mm.
Pixel size is proportional to sensor size and lens resolution. For modern sensors, this parameter varies from 0.6 to 2 microns. The range of values is quite large. The reason is simple: image sensors are divided into two categories – with and without pixel binning.
The first category mainly includes sensors with a resolution of more than 25 megapixels. To the second category – with values within this figure. Smartphone cameras with “honest” sensors always shoot in the stated resolution. They have a relatively large pixel size (1 micron and above). This allows you to shoot well in the dark – more light is captured at the matrix point than sensors with smaller pixels. In good light, the result is even better, but the resolution of the images remains the same. Although, in theory, it would be possible to “squeeze out more.” This led to the creation of binning technology.
Binned sensors combine several pixels of the matrix into one by default. The colors in the photo are averaged, reducing the amount of noise in the final image. The most commonly used binning is 2×2: when building a pixel, instead of one matrix point, four are used. But there are already more progressive sensors with 3×3 binning and nine-point merging. Sensors with a 4×4 formula are already on the way.
There is, however, one caveat. The resolution of the resulting images is reduced as many times as the matrix points are combined to create one point of the frame. For example, 48 Mp turns into 12 Mp, 64 Mp – into 16. And in a 108 Mp sensor with a 3×3 formula, the “hundred” is reduced to a modest 12 Mp. But this is not necessary at all – you can manually switch to full resolution mode. True, it is good only in bright enough lighting.
Basically, binned sensors try to sit on two chairs at the same time. In good light, you can use full resolution, in poor light, use the mode with dot merging to eliminate noise.
The more aperture (aperture) of the lens, the more light it lets through to the matrix. The less noise in the frame and the better the picture is. Flagship smartphones are always equipped with the fastest lenses at the time of release.
The aperture is specified as an f / x value, where f is the focal length and x is the diameter of the entrance pupil of the lens. For cameras, each of these parameters is usually indicated, since there are long-throw and short-throw lenses. Smartphone buyers only need to know the ratio of these two parameters. The focal length of different mobile lenses does not differ too much.
The main cameras on modern smartphones have lenses with apertures from f / 2.5 to f / 1.5. Additional cameras can be equipped with a slower lens, up to f / 4. All other things being equal, the lower the number under the fraction, the better.
In the case of a smartphone, a shot is almost always taken from the user’s hands, and not from a tripod. Therefore, stabilization is an indispensable assistant when shooting in medium and low light conditions. With it, you can get much more frames without blur. The same applies to video shooting – the shaking of the user’s hands will be less noticeable when using stabilization.
There are two types – optical and electronic. Optical stabilization (OIS) is mainly used in flagship smartphones. The OIS image sensor is not rigidly fixed in its housing. It is held in place by magnets that receive data from the device’s accelerometer and correct its position in space.
Electronic Stabilization (EIS) uses a portion of the sensor’s resolution to operate. Therefore, pictures with it will have a slightly lower resolution than usual. Electronic stabilization is not a panacea for blurry frames and video shaking. But if it is correctly implemented, then the end result will be good.
Many flagship smartphones use both stabilizations at the same time to achieve the best results.
Additional camera sensors
Modern smartphones are almost universally equipped with multiple camera sensors, and each of them has its own purpose.
Ultra Wide Angle Lens – A sensor with a wider angle of view than the main lens. Allows you to take a photo “from a distance”, fitting as many objects into the frame as possible. Can be used for landscapes or in confined spaces where there is no way to move farther from the subject.
A telephoto lens is a sensor with a narrower viewing angle than the main lens. Used to realize optical zoom.
A macro lens is a sensor with a short focal length that is usually not available with the main lens. Allows you to shoot small objects at a minimum distance from them. Can be used to take pictures of flowers, insects, or other small objects.
Depth sensor is an additional low-resolution sensor that collects information about the depth of the frame. Works in tandem with the main lens. Enables better implementation of background blur effects.
The monochrome lens is a rare guest on smartphones, yet worthy of a mention. Works in tandem with the main lens. Information from it is processed together with the frame of the main camera. It allows you to improve the quality of shooting in low light conditions.
Despite all the variety, only the last two sensors are used together with the main one. They in one way or another improve the quality of the resulting photos. The rest of the sensors are used only for certain shooting modes. As a rule, the picture quality from them is inferior to the main sensor.
Software processing can increase or decrease the quality of the final image. Two parameters come into play here. The first is the capabilities of the image processing processor (ISP) built into the smartphone’s SoC. The second is how the camera software works on a particular device. The final quality of the image depends on the joint work of the parameters. A smartphone with more advanced software will take better pictures than competitors with similar camera sensors.
Examples of smartphones
Let’s look at examples in practice.
A smartphone with one of the best mobile cameras today, Huawei P50 Pro , has four modules:
The quality of shooting a particular smartphone model depends on many variables, and resolution is far from being in the first place among them. The final picture is much more dependent on the pixel size, aperture and software processing.
Additional camera sensors provide more variety of shooting modes. However, they do not really affect the quality of the photo. When choosing a camera phone, first of all, pay attention to the quality of shooting by the main module.
“Clean” specifications tell a lot. But their implementation by software is no less important. Therefore, when choosing, you can not do without reading reviews on a smartphone camera.