Huawei P30 Pro cameras explained: 5x zoom and better low-light shots through optical wizardry - PhoneArena

Huawei P30 Pro cameras explained: 5x zoom and better low-light shots through optical wizardry

Huawei P30 Pro cameras explained: 5x zoom and better low-light shots through optical wizardry
The Huawei P30 and P30 Pro are now official. They are sleek, fast, and available in a variety of pretty colors, but none of this is as exciting as the cameras these two phones are equipped with. Both devices promise outstanding low-light performance without the use of fancy equipment, allowing you to take breath-taking images in next to no light, while the P30 Pro also boasts a 5X zoom telephoto lens, bringing subjects closer to you than most other phones can. 

How did Huawei fit all this tech in a smartphone? By using a periscope, of course. "A peri-what," you say? We'll explain what this optical contraption does in a bit. Before that, here's a quick look at what these phones offer in terms of camera hardware. Spoiler alert: they're both stacked.

Huawei P30 and P30 Pro camera specs

Huawei P30 Triple CameraHuawei P30 Pro Quad Camera
Main camera40MP, F1.8, RYYB color filter,
No OIS, 1/1.7" sensor
40MP, F1.6, RYYB color filter,
OIS, 1/1.7" sensor
Super Wide-angle Camera16MP, F2.220MP, F2.2
Telephoto Camera8MP, F2.4, 3x zoom, OIS8MP, F3.4, 5x zoom, OIS
Time-of-Flight CameraN/AUsed for depth sensing

Some of these camera features we're already familiar with. Super wide-angle cameras have been a staple of LG phones for a while, and one can be found on Samsung's Galaxy S10 phones as well. They let you fit much more in the frame without having to step back, which makes them useful in tight situations. The Time-of-Flight camera on the P30 Pro is also something we've seen before. Its purpose is to gather depth information for better background blur effects, and here you can read how ToF cameras work

Huawei's RYYB color filter, on the other hand, is unique. It allows the 40MP main cameras on the P30 and P30 Pro to gather more light, thus improving low-light performance. And the P30 Pro's 5x zoom telephoto camera bends light much like a periscope to bring distant objects closer with minimum losses in quality. 

A closer look at camera zoom. How does it work?

Here's a simplified breakdown of how camera zoom does its magic. Chances are you're already familiar with digital zoom – the kind of zoom you'll find on every single phone. This is easily done by "stretching" the image in software, and while your subject does appear closer in the photo, you don't gain any detail. 

Optical zoom, on the other hand, is done with optical hardware. The lens is physically moved away from the sensor which results in a narrower field of view. As a result, the subject is brought closer with minimal degradation in image quality. This is why the lens on a dedicated camera extends outward when zooming in.

Naturally, optical zoom lenses are bigger and more sophisticated than fixed ones, which is why modern smartphone cameras approach quality zooming differently. More and more phones now offer multiple cameras at the back, one of which is a telephoto camera. These telephoto cameras still use fixed lenses. They don't actually zoom optically back and forth. However, these telephoto lenses have an optically narrower field of view – they're zoomed in relative to the main cam. The telephoto camera on the Huawei P30 Pro provides 5x zoom, which is greater than what phones like the iPhone XS (2x zoom), the Galaxy S10+ (2x zoom), and the Huawei Mate 20 Pro (3x zoom) can deliver.

Huawei P30 Pro delivers real 5x zoom with clever optics

But again, the more you want to zoom in, the further away your camera lens needs to be from the sensor. In a typical smartphone camera assembly, that distance is about 4 millimeters (less than three sixteenths of an inch). To get 5x optical zoom within the same camera system, that distance needs to increase 5 times. Would you be okay with having an inch-thick camera bump on your phone? We doubt it.

To achieve the 5x zoom on the P30 Pro's telephoto camera, Huawei has done two things. Firstly, the image sensor is relatively small, and a smaller sensor requires a shorter distance between the lens and the sensor to achieve the same field of view. Secondly – and this is the clever part – a prism bends light 90 degrees. Instead of sticking out, the optics are parallel to the back of the Huawei P30 Pro. This is how the optical length necessary for 5x zoom is provided in a phone only 8.4 millimeters thick. This same principle is used in periscopes, which are optical devices allowing one to see around obstacles. 

To be clear, the telephoto camera on the Huawei P30 Pro has a fixed lens, so it only does 5x zoom relative to the main camera. If you zoom in at 2x, for example, that's going to be digital zoom from the main cam. Interestingly, in the range between 3x and 4.9x zoom, the phone uses both its main and telephoto cameras to capture visual information, which should result in more detail. In the range between 5x and 50x, only the telephoto camera is used, with all zooming beyond 5x done digitally.

Huawei's RYYB color filter explained

Of course, most of the time when shooting with the Huawei P30 and P30 Pro, you'll be using their main, 40MP camera. What's unique about it is that it uses a different color filter, resulting in 40% better light absorption compared to the sensor on the P20 Pro.

To explain how such a considerable gain is achieved, we need to shed light on how digital imaging works. You probably know that a typical modern display is made of pixels, and each of these pixels has a red, green, and a blue subpixel. Colors are produced by blending light from these subpixels, allowing each individual pixel to produce any color we want. But camera sensors are different. They do have pixels as well, but a single pixel can't capture any color on its own. Each pixel has a filter over it allowing only red, green, or blue light to pass through. These color filters are arranged in a pattern and are collectively called a Bayer filter (invented by Bryce Bayer of Eastman Kodak some 43 years ago). 

On one hand, the Bayer layer allows each pixel of an image sensor to capture full color. A pixel already captures one of the three primary colors, and values for the other two primaries are estimated from its neighbors. However, a significant amount of light is blocked in the process. 

Most image sensors have color filters arranged in a red-green-green-blue (RGGB) pattern, but Huawei's 40MP sensor swaps all green pixels with yellow ones (hence, the RYYB abbreviation mentioned above). Since yellow light is made of green and red light, a yellow filter lets more light pass through, which is how the gain in light absorption is achieved. And the value for green light is estimated by subtracting that of the neighboring red pixels. 

So, this seems like a super simple trick to boost a camera's performance. Why has nobody thought of it before? Well, as a matter of fact, experimentation with alternatives to the classic Bayer filter has been going on for decades. Nikon and Canon are known to have used CYGM filters (cyan, yellow, green, magenta) in their cameras, but while this filter may have better dynamics range, it lags in terms of color accuracy. Another example would be the first-generation Motorola Moto X which used a RGBW (red, green, blue, white) filter to let more light through, but again, its camera didn't stand out in any way with its image quality. Some phones, including a number of Huawei flagships, had multi-camera setups where a color camera was paired with a monochrome one with no filter at all. Visual data from both was combined to produce a superior image. It's a trend that's fading out.

The classic RGGB color filter, however, remains the most widely used as it is old, familiar, thoroughly tested tech. It is easier to implement and the images are easier to process. We applaud Huawei for trying something new – for going through all the trouble that implementing a new color filter requires (and there's more of it than one might assume). But only time – and more thorough camera testing – will tell if Huawei's color filter truly outperforms the classic Bayer filter in every way.
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