- Tram Ho
Equipping smartphones with the best cameras is a never-ending battle. What many companies are advertising the most is definitely the resolution (also known as the number of ‘dots’) that the camera can capture, we’ve seen this number increase from 16MP to 40MP, then 48MP , 64MP and up to 108MP on the latest smartphones from Samsung and Xiaomi. But in fact, one factor is much more important to image quality than resolution: the size of the camera sensor .
The image quality depends on the amount of light the camera captures
In essence, ‘taking a photo’ is the job of capturing the light of the lens and the image sensor of a camera. The higher the quality of the lens, the larger the sensor will be, the more light will be, and factors such as color, sharpness, and dynamic range will be guaranteed. This is why professional cameras, although only 16MP, 24MP still produce better images than smartphones with cameras up to 108MP.
Most sensors on the smartphone are 1 / 2.55 inch, with a diagonal of about 1cm, for comparison, the camera sensor usually has a larger diagonal of 2.54cm, 4-5 times larger in area. However, there are also many smartphone companies equipped with large sensors such as Huawei P40 with size 1 / 1.28 inches.
With smaller sensors, to get the same amount of light, you will have to increase the light sensitivity (ISO) or long-term shooting. If taken longer, due to the vibration of the hands of the photographer, the image may be blurred. Conversely, increasing the light sensitivity factor will create small noise spots on the image, making the image quality worse. Equipping high-quality lenses with a large aperture (aperture) also becomes difficult because the criteria for making smartphones are slim and compact to fit into the pocket of a pants.
Photo taken from Google Pixel 4
And from the Nikon D3300, a budget DSLR
On a sensor there are many bright spots, normally each pixel will be a bright spot. The larger the sensor, the more light these points will be able to capture, so that the dynamic range of light (the difference between light and dark areas) will also be improved.
If we increase the resolution on the same sensor size, then the light points will certainly be reduced in size, which is a simple mathematical operation. Even if the light points are placed too close together, the ‘leakage’ of light from one point to another can occur, creating noise spots on the color patches in the image.
The large image sensor is very important
So we can see, having a large image sensor is very important, it’s even more important for high-resolution models. Currently smartphones are very high resolution, Samsung S20 Ultra even ‘climb’ up to 108MP. In addition to the increase in resolution, these models have increased the size of the sensor, although not able to produce beautiful photos by specialized cameras, but also have narrowed the distance.
Smartphone companies have also adopted a new technology, which is pixel binning, turning 4 or 9 pixels into 1 to increase the size of the light. This technology will reduce the resolution, but will be useful in the case of low light, reduce noise as well as increase color quality.
Another advantage of the large sensor is that it is possible to create large background blur (bokeh). This is an effect that was previously only possible with professional cameras and large aperture lenses, but in recent times when smartphones have more and more sensors, this effect has also appeared. without having to resort to ‘virtual’ font deletion algorithms.
Compare sensors of current smartphones
Image sensor size on smartphones is getting larger and bigger. In 2020, there are already models with sensors that surpass 1 / 1.5-inch records created by Nokia Lumia 1020. Large sensors mean the new models will be thick, have large rear camera clusters, but have Perhaps both manufacturers and users have accepted this to get better picture quality than ever before.
Table comparing the sensor size of high-end smartphones today, compared to Lumia 1020
In the comparison table, we see the Pixel 4 and iPhone 11 Pro at the bottom, but these are still the models with very high image quality. So what makes this contradiction?
There are still many other ‘variables’
The large sensor is a very important factor that affects image quality, but in reality there are still many other ‘variables’. We can mention the quality of the front lens, image processing capabilities of the chip, the algorithms that it applies.
In recent times, we have heard a lot about the words “Hardware is not as strong as the code”, to indicate the importance of image processing algorithms on new generation smartphones. Therefore, in order to have a perfect smartphone camera, we need to have the best image processing capability, built on a ‘background’ of strong physical elements, in which the sensor size is a big factor.
Source : Genk