Although 2016 is not the first year of the birth of dual cameras, it is definitely a year of concentrated outbreaks. As of mid-July, at least 360 Qi Cool Ultimate, LG G5, LG G5 SE, Huawei P9, Glory V8 and Glory 8 and other 6 models equipped with dual camera phone market, and according to recent news, including The new machines, including millet, Moto and Nubia, are all on the road to developing dual cameras. The reason may be that the iPhone may have launched a dual camera before it was revealed, but it is definitely not a dominant factor. After all, it is not realistic to immediately make changes based on unclear rumors. Today, we came to chat about the explosion of dual cameras in 2016.
To understand the reasons for the introduction of a technology, we must understand the role of this technology. Friends who are interested in the history of dual cameras can look at the “Behind the Fire Behind Two Cameras†written by their colleagues. We mainly look at the major features of this year’s mobile phones equipped with dual cameras.
LG G5/LG G5 SE: Join Another Wide Angle Lens
The dual cameras on the LG G5 and G5 SE are indeed "two cameras." Open the camera with different camera angles, the ordinary camera is the same as a regular mobile phone, and the other is a wide-angle lens, which brings a wide angle of 135 degrees and can accommodate a wider area. The two camera pixels have different apertures, but the quality of the ordinary lens is still more powerful.
LG G5 equipped with a 135 ° wide-angle lens
Careful observation will also find that the two main cameras of the LG G5 are not quite the same design as other dual camera phones. This will be discussed later. The dual camera system working as two cameras is relatively mysterious. The addition of another camera simply makes the camera more comprehensive in perspective and more gameplay.
The two lenses are far apart
Below you can compare the photos taken with the two cameras of the LG G5 SE in the same position. You can see that the effect of the wide-angle lens is very obvious. The first sample that originally used a normal lens shot only a small part of the area, but after changing to a wide-angle lens, the picture content was enlarged by about 2/3. The originally invisible scene can be seen this time.
Scene shot using ordinary lenses
Scene shot using the wide-angle lens at the same position
Although the wide-angle lens photographing effect is obvious, the photographs taken by the two lenses have not been synthesized as we expected, and therefore the quality of each other cannot be promoted. In addition to the LG G5/G5 SE, there is another way to go.
360 cool flagship, Huawei P9, glory 8/V8: color + black and white synthesis
After careful study, it was found that it is entirely possible to combine the dual-camera technology and the synthesizing principle used in 360 Qikuo Ultimate, Huawei P9, and Glory 8/V8. Overall, these four phones use a lens that can recognize color information plus an equal-pixel camera that only recognizes black-and-white information (this is important, reducing the difficulty of the synthesis of the two photo algorithms). Lens system. As we know, the CMOS sensor inside the camera camera itself can not feel the light of all colors, so you need to arrange a layer of Bayer filter responsible for distinguishing colors in front of the sensor. But it is also the presence of this filter, so that the details of the subject are lost. The main purpose of the existence of another black-and-white lens is to "lose" details of the losses through later algorithms.
Color + black and white dual lens module composition effect
The specific schematic shown above, in the previous "is the inevitable or Shantou iPhone 7 or dual camera? The main purpose of the dual camera and the difficulty of its implementation have been summarized in detail and will not be described here.
Comparing these mobile phones, the author found a difference in appearance, that is, in addition to 360 odd cool flagship, the other several are horizontally placed two lenses, the specific location is also different. But compared with the LG G5/G5 SE above, the distance between the two cameras is much smaller. Taking into account 360 odd cool flagship, Huawei P9, glory 8 and several other phones need to synthesize proofs, the lens module distance is small in order to reduce the late algorithm to correct the difference between the two lenses.
360 cool flagship
360 odd cool flagship real proofs
Judging from the aspect of quality, the author previously conducted an experiment that blocked a black-and-white lens and allowed only color lenses to be imaged (see “Unlocking the Shadows and Exploring the Secrets of the Glory V8 Dual Lensâ€). The experimental results showed that The addition of dual cameras can really improve the quality of the proofs, but the difference is not obvious. The specific reasons will be explained in detail later. Let us review these dual camera phones and real proofs.
Huawei P9 Parallel Dual Lens
Glory 8 Twin Lens
Huawei P9 really making proofs
Color + black and white dual lens module composition image principle
In fact, I believe we are most concerned about the use of a dual-lens module mobile phone, and the same scene shot with a single color lens, the quality of all aspects of how much will increase. This point we have to elaborate from the way of photo synthesis in the camera.
The following synthesis logic was given in a report on a two-lens-module in-camera photosynthesis algorithm. In simple terms, the electronic data of the two shots (black and white, color) were taken respectively, after image synchronization and pixel calibration. Several processes, such as picture synthesis, are finally presented to us in JPG format.
Color + Black and White Dual Lens Algorithm Logic
The problem then appears in the final step of “picture synthesisâ€. Three steps may occur in this step. They are “black and white photos as main referenceâ€, “color photos as main reference†and “only color photos as referenceâ€. (mono represents black-and-white photographs) Analyze and guess, these three situations are in “the situation where the light and shade are strong but the color contrast is generalâ€, “the situation where the color contrast is strong but the contrast between light and shade is common†and “the light is strong but the contrast between light and dark is not strong The use of "scenarios".
Color + black and white dual lens noise control
Having understood the above process, it is not difficult to understand that the dual camera system does not improve our picture quality in all environments. In some scenarios, the final performance and the individual camera effects may not be significantly different.
Let's take a look at the difference in the noise control performance between the synthesized photo and the individual color photo. Through the experimental data in the report, we can see that the signal to noise ratio represented by SNR is more in the composite photo, indicating that the corresponding noise is less.
The above is just the effect of the color + black-and-white dual camera module given by a laboratory environment. The specific use effect is welcome to test by yourself.
More crazy designs than double shots have emerged
From one shot to two shots, is the more shots the better? From the point of view of cell phone size and design, it is unrealistic to see too many lenses on a mass-produced mobile phone, but in the field of cameras, light-field cameras have already reached the extreme.
Light Field Camera Lens Photographic Principle
Lytro light field camera's biggest feature is the first photo after focusing, in the light field camera lens can simultaneously receive 40 million beam (second generation) light path, while shooting hundreds of photos, and double lens mobile phone is much higher than. However, problems such as slow imaging and high selling prices have made the light field cameras not widely popularized. On the other hand, multi-lens mobile phones, from the viewpoint of image quality enhancement, are at least very limited at present; in terms of cost and design, there will not be more shots added to mobile phones in the future. Twin shots may be the most mobile phones can reach, and it is not necessary to blindly join twin shots before fundamentally solving people's pain points.