The redmi Note9 Pro now has 1 million pixels
For example, in just two years from the end of 218 to the end of 22, the main camera specification of the thousand-pixel model has jumped from 12 million pixels to 18 million pixels, and the mainstream CMOS size of the flagship image model has also "expanded" from 1/2.6 inch and 1/2.3 inch. Not to mention the increase in the number of cameras. After all, two years ago, who would have thought that now four or even five cameras have been "everywhere"?
But if we tell you that today's smart phones have not made fundamental progress in a key imaging technology for a long time, and even regressed compared with the past, can you think of what it is? The answer is zoom.
Some friends may say that the mobile phone two years ago didn't have such a strong zoom capability. Look at the current products, there are several 6x zooms and 1x ultra-long zooms. Isn't this a technological progress?
unfortunately, it's not, because what we want to talk about is actually the implementation method of "zooming" of smart phones. In other words, it is the essential principle of "zoom".
The mainstream relay scheme actually has many problems.
How does the smartphone achieve zoom shooting? Simply put, there are two main technical solutions.
first of all, it is the most mainstream "multi-camera relay zoom". Simply put, it refers to equipping a smartphone with multiple camera modules with different focal lengths, and then switching between them to achieve the "zoom" effect.
for example, suppose a mobile phone has three cameras, in which the main camera is a wide angle with a focal length of 25mm, the auxiliary camera 1 is a super wide angle with a focal length of 16mm, and the auxiliary camera 2 is a telephoto with a focal length of 5mm. Then, by switching the lens, this model can realize the "zoom" of 16mm, 25mm and 5mm focal lengths.
but in this way, the problem arises. First of all, if the user happens to want to use a focal segment located between these three focal lengths, how can he satisfy Ta?
the answer is simple, which is achieved by using a lens with a lower focal length and the algorithm of digital magnification. For example, for a focal length of 2mm, the model in this example usually switches to a 16mm super wide-angle sub-camera, and then enlarges the picture according to a certain proportion; For the focal length of 35mm, we use the main camera of 25mm, and then enlarge the picture.
Compared with pure optical zoom, digital zoom has a very serious image quality loss.
As we all know, digital zoom algorithm or "digital zoom" itself will lead to obvious image loss, so for the common "relay zoom", manufacturers often set several buttons with fixed focal length in the camera interface, corresponding to the original focal length of several lenses respectively. In order to let users use the intermediate focal section as little as possible, so as to avoid the problem of amplification loss of the intermediate focal section.
compared with the main camera, the auxiliary camera of most mobile phones will be shrunk in different degrees, and the flagship is no exception
Secondly, as we just said, for most smart phone products today, only the CMOS size and lens materials of the main camera are the best, while the auxiliary cameras such as ultra-wide angle and telephoto will be somewhat shrunk. This means that once the zoom function is used, even if it is not the intermediate focal length, the relay zoom will inevitably lead to the problem of image quality degradation.
The emerging outsole algorithm scheme can't be perfect either.
Since relay zoom has the problems of image quality reduction of the secondary camera and digital amplification loss of the intermediate focal length, is there a zoom scheme that can solve these two shortcomings?
Needless to say, there is. This is the "outsole fusion zoom" brought by Samsung on the Galaxy S2/S2+ earlier this year.
did you find it? Yes, unlike the traditional "relay zoom" design, the "telephoto sub-camera" of Galaxy S2/S2+ has the same size as the main camera and higher pixels than the main camera. And their "telephoto sub-shots" are actually not telephoto at all, because their focal length is actually only 2mm more than the main shot.
In this way, it means that for Galaxy S2/S2+, their so-called zoom is actually an "algorithm" effect based on the fusion of main and secondary shots, AI calculation, and cropping by the large bottom and high pixels of the secondary shots.
However, due to Samsung's special zoom design, the CMOS specification of the secondary camera itself is far beyond the conventional scheme in the industry. Even though it is a zoom effect realized by an algorithm, in the scoring system of DxOMark, for example, the zoom score of Galaxy S2+ (81 points) is much higher than that of Galaxy S1+(68 points) and iPhone 11 Pro Max(74 points) which use a small bottom and low pixel sub-shot+true double focal length lens. It is proved from the result theory that this unconventional design is effective.
moreover, because the telephoto end of Galaxy S2/S2+ is essentially realized based on algorithm in the whole process, it can avoid the experience that the traditional "relay zoom" has better image quality at a specific focal length, while the image quality at other focal lengths is degraded.
However, even though this dual outsole fusion zoom may be a little better than the conventional relay zoom, it is still not the most ideal zoom scheme. Because no matter how big the base and high the pixels are, the fused image will gradually decrease with the enlargement (zoom) because there is no real optical zoom lens.
Will the real continuous optical zoom be revived next year?
Having said that, what kind of design can really realize the continuous shooting zoom, and the image quality will never be attenuated during the zoom process? Quite simply, it is a "continuous optical zoom" design.
the so-called continuous optical zoom, as its literal meaning shows, is to directly use a single periscope camera with multiple sets of optical zoom lenses to realize the whole zoom process from the wide-angle end to the telephoto end.
in this process, CMOS does not switch, so there will be no problem of image quality degradation caused by the shrinking specifications of the "secondary camera" compared with the main camera. There is basically no need for additional zoom algorithm, so the resolution of the picture can always be consistent in principle to achieve the best zoom image quality performance.
is this a camera? No, it's a mobile phone.
The most important thing is that "continuous optical zoom" is not the latest design at all. It appeared in the mobile phone industry many years ago. As early as 27, Sony Ericsson introduced a 5-megapixel camera phone SO95iCS with a built-in triple periscope anti-shake optical zoom, a zoom range of 4.5-13.5mm and a variable aperture of F2.8~F5.4. Of course, it is not a smart phone. At best, it can only be regarded as a precedent for the periscope zoom of camera phones.
in 215, ASUS cooperated with Japanese optical manufacturer HOYA, and successfully inserted a 1-piece continuous zoom zoom periscope optical lens with triple telescopic magnification and OIS optical image stabilization into the Android phone. It is not only much more complex than the current mainstream smartphone lens, but also the first one to realize the continuous variable optical zoom with 1 ~3 times focal length in Android models without the assistance of algorithms.
ASUS customized a 1-piece continuous zoom lens module for Zenfone Zoom at that time
To some extent, we can say that the "true optical zoom" design of smart phones has already had a ready-made scheme. However, the reason why this design that is really good for image quality was generally not followed up later may be due to the fear of its cost and the thickness of the fuselage. On the other hand, it may be that more cameras look more scary.
Fortunately, with consumers' demand for smart phone imaging ability, it has gradually returned to the essence of image quality and shooting experience from simple "more lenses" and "higher pixels", and mobile phone manufacturers seem to have finally made corresponding preparations.
firstly, at the beginning of this year, vivo launched a concept mobile phone called APEX 22. It is equipped with two cameras, one of which is equipped with a micro-pan/tilt camera developed by vivo, and the other is a telephoto lens with continuous optical zoom design. Obviously, micro-pan/tilt now has X5 Pro and X6 series products which have just been released for two generations, so we can't help wondering when vivo is going to mass-produce continuous optical zoom lenses.
Secondly, in July, 22, Guo Ming, a securities analyst, predicted that Apple would have at least one iPhone model with a periscope optical zoom design in the future. More importantly, as early as 215, an exposed design patent showed that Apple had mastered some technologies related to continuous optical zoom lens, and even completed the design related to optical image stabilization of periscope lens. It is only because some key parts of this design have encountered patent obstacles that can't be bypassed that the iPhone has not been able to get rid of the design of relay optical zoom.
Apple's patent for the structural design of continuous zoom lens
According to a report published by foreign media DigiTimes, it seems that Apple finally decided to adopt a better continuous optical zoom design to replace the existing multi-camera zoom scheme. In order to do this, they will seek authorization from manufacturers such as Samsung and LG, or bypass patent restrictions through OEM services.
judging from the relevant information, at least vivo and Apple are likely to have the ability to revive the continuous optical zoom design, or are already preparing for it. And considering their own position in the industry, it seems that we can expect a new wave of changes in the zoom design of smart phones in the future.