Mythbusters: Is Sony Xperia XZ Premium seriously distorted?

IT 168 evaluation some time ago, Sony Xperia XZ Premium was listed in China. As a leader in MWC 20 17 at the beginning of the year, this flagship mobile phone loaded with black technology won wide attention as soon as it went on the market. Of course, even if a product gets more awards and attention before listing, it is empty talk, and it can stand the test of the market in the end, and it is its greatest belonging to be recognized by consumers. Therefore, Sony Xperia XZ Premium has been on sale in China for about a month. Have you finished the market research?

According to the news of Sony Mobile Phone Post Bar, many users found serious distortion when taking photos with Sony Xperia XZ Premium, and then many media reported this problem. At this time, a friend who just took a fancy to Sony Xperia XZ Premium was puzzled. This mobile phone was originally designed to take pictures, but there was a distortion problem. Is it serious? Do you want to buy it? This issue of "mythbusters" starts from this question and answers the doubts of this kind of consumers.

First, what you see is not distortion, but perspective!

Aside from those photographers, most mobile phone users will intuitively tell him that it is because of the lens deformation when they see a face deformation or object deformation in a photo they take. In fact, the professional name of this phenomenon is not distortion, but perspective. The so-called perspective is simply the phenomenon of "the near is big and the far is small". For example, girls know that photographers can show their legs from bottom to top, and they can show their faces when they look up at 45 degrees when taking selfies. This is actually the perspective principle applied to camera imaging.

▲ Schematic diagram of perspective phenomenon (picture from photographic notes)

▲ Visual angle function demonstration in ▲Snapseed, the principle is perspective.

If you still don't understand, you can open retouching software such as Snapseed, import a photo at will, and slide in the options of deformation or perspective. What you see is the perspective phenomenon formed by the same algorithm.

▲ Schematic diagram of distortion phenomenon (picture from photographic notes)

So what is distortion? In fact, the lens consists of a plurality of concave mirror and convex mirrors. The lens of a general mobile phone is composed of six mirrors. In this way, the pillow-shaped and barrel-shaped distortions are inevitably brought. The easiest way to check whether the mobile phone is distorted is to take a picture of the panel printed with "Tian Zige" with the mobile phone to see if the original straight line will "bend". However, due to the images of various test factors, many netizens did not guarantee that the lens was completely parallel to "Tian Zige", which led to a certain perspective phenomenon and affected the test results. This not only misleads Xiaobai users, but also confuses the concepts of distortion and perspective.

Second, is Sony Xperia XZ Premium distorted?

Generally speaking, the lens structure of a mobile phone is simple and does not involve optical zoom (the so-called optical zoom of those dual-camera phones is realized by algorithm or camera switching, not traditional optical zoom), so there is basically no distortion. Of course, some low-quality mobile phones are also excluded. In order to dispel everyone's concerns, I brought Samsung Galaxy S8 and Sony Xperia XZ Premium, which are both single lenses, for comparative testing.

▲ The picture on the left shows the shooting of Samsung Galaxy S8 without distortion correction, and the picture on the right shows the shooting after opening.

▲ Sony Xperia XZ quality shooting

Because the camera of Samsung Galaxy S8+ supports distortion correction function, I took two photos without turning it on and off. Judging from the test results, neither Samsung Galaxy S8 nor Sony Xperia XZ Premium will be distorted. During the test, both phones took photos in automatic mode. Because the cameras of these two mobile phones have no built-in level function, there is an objective error in the test process, but this error is not enough to overturn the conclusion. Therefore, there is no distortion problem in Sony Xperia XZ Premium, and there is basically no distortion problem in the lenses of most mobile phones.

3. What do you think of Sony Xperia XZ Premium?

The root of the problem lies in the perspective. I can tell you clearly that both professional cameras and mobile phones have perspective phenomenon, which absolutely exists. It's just that photographers can minimize the negative impact of perspective according to the needs of composition or later algorithms. As far as mobile phones are concerned, the wide-angle lens basically used in mobile phones on the market is easier to see through.

▲ Schematic diagram of perspective phenomenon (picture from network)

Just now, we also mentioned the concept of "near big and far small". For example, we usually shoot a building, which is very big. If we want to film it all, we have to film it backwards. In this way, the original parallel lines become convergent oblique lines, forming a perspective. Just like we usually take pictures of buildings with mobile phones, buildings that were originally rectangular will eventually be imaged as trapezoid.

Fourth, if the influence of viewing angle on photos is reduced?

In fact, when shooting a big scene or scene, the perspective phenomenon has little effect. The main problem is that when shooting portraits, if the operation is improper, it will easily lead to facial deformation. So how can we avoid unnecessary perspective?

In fact, most of the photos we see on the Internet with obvious perspective effect are taken by people who lack basic photography knowledge. As long as you pay attention to two points when shooting portraits, you can easily avoid unwanted perspective effects.

1, try to keep the camera parallel to the model and avoid shooting up and down.

2. If you want to show a character's long legs or small face by shooting up or down, try to compose the character in the middle of the picture.

In addition, if you want to modify photos with obvious perspective, in fact, many retouching apps have this function at present. Setting options is generally called perspective or deformation, but the name is different and the reason is the same.

Summary:

In short, as Sony's official reply, the perspective phenomenon of Sony Xperia XZ Premium exists in ordinary smartphones and is within the acceptable range. If you know a little photography skills, you can easily avoid those unnecessary perspective effects. In addition, the picture distortion caused by this perspective can be adjusted by software algorithms. At present, this function has been added to the camera function of Samsung mobile phone. I hope Sony officials can pay more attention to it and increase the perspective correction function.