Why is the camera block so big and protruding? You can't argue against technology and physics
The camera has become a measure of the evolution of smartphones, in recent years this direction of development of mobile devices has flourished. What was not previously available for mobile cameras is now considered commonplace and familiar. But a good camera cannot exist without rising above the "back". And users really want everything to look neat and the sensors are flush with the body. Is it possible to make the camera take great pictures without looking like a foreign body or “bump” on the back?
Those in the thread already know the answer. At this stage there will be no compromise. If you want good photos, you will have to put up with a protruding camera block. Of course, you can make sure that the platform with the modules does not stick out, but the quality of the pictures in this case is unlikely to suit you. Why is that? Let's try to figure it out.
But before we start talking about the protruding camera, it will not be superfluous to recall a number of points. Let's start with the fact that the camera includes such elements as a matrix, optics, an RGB filter for determining colors, protective glass, substrates and other components. And in the article we will mention such concepts as resolution, matrix diagonal and focal length.
The matrix is responsible for the finished picture and it accounts for several millimeters. So, the fairly replicated Sony IMX586 sensor has a physical diagonal of only 8 mm (1.2 ʺ), and the flagship Sony IMX700 sensor has 7.5 mm (1/28 ʺ). The size of one pixel in modern sensors is 0.8 mm, and sensors with 0.7 mm pixels have already appeared. This is very small, and opponents of small pixels argue that going down the path of their reduction is akin to a crime - it is difficult for them to capture enough light. Lack of light leads to the appearance of noise, which means that the quality of the image deteriorates.
Experience has shown that it is difficult for a sensor smaller than 1/3” to offer optimal image quality. All main smartphone cameras have dimensions in the range of 1/2 "-1/3", with rare exceptions (Huawei P20 Pro, - 1 / 1.8"). If you make the matrix larger, it will turn out to be excessively cumbersome, if it is smaller, the photo quality drops.
Another important parameter is the focal length. The lens collects light at the focus point. The distance from the focus point to the lens is called the focal length, and it is measured in millimeters. This distance determines the viewing angle and degree of magnification. A longer focal length narrows the angle of view, but at the same time increases the magnification. The higher the magnification, however, the more noticeable the differences between objects in the foreground and background. How it actually works can be seen in the picture below.
Another important point is the crop factor, which directly depends on the size of the matrix. The lens captures the image regardless of the sensor size and the final image is cropped based on the size of the sensor. Crop factor plays an important role in wide angle cameras and zoom lenses.
A small sensor results in more framing and offers a smaller angle of view. The focal length increases and a zoom effect is created. That is why in telephoto lenses they prefer to install sensors of small sizes.
It just so happens that modern image sensors for the most part offer a thickness of at least 8 mm. This is relatively small, but applicable to a smartphone whose thickness varies within 8-9 mm, it is easy to understand that it is difficult to fit the sensor inside flush with the case. At the same time, do not forget about the need to install lenses and protective glass, and this is an “add-on” a couple of millimeters to the thickness of the entire camera system. It is also important that not the entire thickness of the case is allocated for the camera, there is also a display that also “eats off” a certain space.
When big sensor and zoom matter
So it turns out that manufacturers at the present stage of development have only two options: to increase the thickness of the case, making it bulky, or to offer a protruding camera block. Of course, provided that the creators want the smartphone camera to create high-quality photos. You can install a very tiny sensor, but then you have to reduce the resolution, and not everyone agrees to do this.
Of course, there are those who will cite the same iPhone, Pixel or Xperia as an example, where the cameras stick out, and their resolution is small by modern standards. But there are other factors involved. So, some seek to increase the zoom. And here the focal length comes to the fore, allowing you to zoom in on the image. Here it is necessary to offer a greater distance between the matrix and the lens, and this is also achieved by installing special mirrors that reflect light. As a result, the desire to increase the zoom value leads to an increase in the thickness of the camera system, primarily due to the telephoto lens.
It is also not uncommon for manufacturers to install larger sensors that are able to capture more light and, accordingly, the quality of photographs improves. The larger the sensor, the more it sticks out. Do not write off the desire to offer a crop factor, and the larger the sensor, the greater the focal length required. Failure to do so may result in an increase in the viewing angle, which may be undesirable under certain conditions. For example, in multi-module cameras, where each of the sensors must offer a certain degree of magnification.
We do not write off the distortions that are most pronounced at the edges of the lens. A larger crop and a large sensor increase the degree of distortion. Typically, this problem manifests itself in small lenses with a wide aperture.
You can solve the problem by installing high-quality lenses. But due to the compactness of modern devices, this is not an easy task to do. Another option is to change the focal length so that the frame is taken from the center, where there is less distortion and the image quality is higher. But even here you can not do without a larger focal length and, as a result, the size of the camera increases.
The bulging camera is good
All of the above confirms that smartphone manufacturers have to find a compromise between physics and image quality. And in these studies, the protruding camera unit is an absolute must if you want to offer good quality photos. The desire to "catch up and overtake" DSLRs dictates the need to install large sensors and increase the zoom value. And this, in turn, is a consequence of the fact that good mobile cameras will continue to rise above the back of smartphones.