How a can of Coca-Cola can improve the image quality of our smartphones

Vivo invited German optical manufacturer Zeiss to its X80 Pro. We explain to you concretely what this partnership could bring and what their approach was.

Vivo X80 Pro in front of a color test card. // Source: Frandroid – Chloé Pertuis

marketing nonsense or really good news for your photos? The partnership between Zeiss and Vivo, like Hasselblads with Oppo and OnePlus or Leica with Xiaomi, raises many questions.

During a meeting with Zeiss engineers, we were able to better understand what the Chinese smartphone brand got out of this partnership. For neither the lenses nor the optics are manufactured by the German imaging specialist. No, its role is somewhere else. This is to provide expertise in three areas (among others): color quality, definition and anti-reflective coatings. We give here a small overview of the three.

Keep in mind that everything shown to us here is not a trade secret and therefore there is reason to believe that it is only the tip of the iceberg. Nevertheless, these elements help to better understand the approach of optical specialists working on smartphones.

A can of Coca-Cola and a Milka tablet to test the colors

The first tool used by the Zeiss engineers that we wanted to show you is a simple box that allows certain colors to be reproduced faithfully and whose lighting can be varied. Here, for example, Zeiss showed us a box that allows us to test 18 colors. The interest is to see how much the colors vary when the lighting e.g. warming up. Green, for example, tends to vary slightly. It is on this basis that the engineers will be able to work.

Zeiss visits Vivo (1)
A box to monitor the variety of colors depending on the light. // Source: Frandroid – Chloé Pertuis

“What we are trying to copy is not a physical measurement of color, it is a combination of illumination and how the eye receives color”explains David Abreu, an engineer at Zeiss, during a meeting with the press. Frandroid participated in it.

Then comes another test, still on color, an oh-so-important topic. It begins in a strange way with a painting that especially contains a can of Coca-Cola, a piece of lawn or even a bar of Milka chocolate. If this sounds a bit farcical, it’s actually very serious.

There are so-called memory colorssays the Zeiss engineer. These are colors that we know users will have expectations of. They are also the ones who will jump out of you right away. »

We are thinking here, for example, of the green in the grass, the purple of the chocolate bar or the characteristic red of the can. In addition to the anecdote, these colors are ingrained in everyone’s memory. Moreover, the engineer is for a time transformed into a philosopher when he explains to us: “People remember these colors well, but not necessarily in the same way as what you actually see in the scene. There may also be variations between regions of the world. This is something we have measured. » Therefore, Vivo has decided to leave the choice between natural colors (called Zeiss colors) or those that are a little more flashy, but coveted by the largest number.

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Vivo X80 Pro on the test bench. // Source: Frandroid – Chloé Pertuis

Other objects in this painting respond to another problem. We have, for example, a sheet of aluminum foil, which makes it possible to ” test highly localized high-intensity light sources”, Further details David Abreu. We can also distinguish between a brush, which makes it possible to measure the reproduction of details well.

How to test the definition

Zeiss engineers also showed us how to test the definition of an image. The goal is simple: to avoid deformations as much as possible. The test this time is based on a set of circles with black and white stripes. The goal is that the closer we get to the center of the circle, the more complicated the definition will be to distinguish.

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Here is a tool used to determine if the device definition is good. // Source: Frandroid – Chloé Pertuis

The other interest of this test is that it makes it possible to distinguish whether there is an asymmetry or problems on the edges of the image. In fact, it is not difficult to notice an anomaly on perfect lines.

Anti-reflective coating to play with light

If you’ve looked closely at the back of the latest Vivo X80 Pro, you may have noticed a strange red “T *” symbol.

Vivo X80 Pro Zeiss
Vivo X80 Pro benefits from Zeiss expertise in the image // Source: Anthony Wonner – Frandroid

The presence of this T * is intended to inform the consumer that the lenses on this device are covered by a special coating. Coating consists of applying a very thin layer (less than one µm) of a very specific texture to a lens.

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The difference between anti-reflective and non-reflective coating is obvious. // Source: Frandroid – Chloé Pertuis

Its purpose is mainly to reduce the reflections created by the lenses. It sounds simple like that, but it’s a big problem. “On any lens, you have 95% of the light that passes through. You can say ‘it’s not that bad’, but the problem is when you start placing several in a row.” For example, we may have a lens in the center of all the others that reflects 5% of its light toward the before, which returns toward the after, and so on.

That’s also how we get onelens flarethis famous effect so dear JJ Abrams, director ofStar warsepisode 7. Once this is mastered, there may be some aesthetics in it, but overall it is a flaw in an image that Zeiss promises to correct by applying a coating to the lenses.

Reducing glare has other benefits. One thinks, for example, of a significant increase in the contrasts, because the amount of diffused light in the image is better controlled.

What is the difference between Leica and Hasselblad?

This work with the lens, even if it only adds a little coating, seems to us for once as a specificity of the partnership between Zeiss and Vivo. As far as we know, Hasselblad is happy to help Oppo and OnePlus with color calibration, while the exact extent of the partnership between Leica and Xiaomi is not yet known.

On the other hand, it is likely that the color procedures or definition that we have just presented to you are generally the same with other manufacturers. Let’s add that many manufacturers like Samsung, Apple or Honor do not use such partnerships, which does not prevent them from being well placed in the various rankings of the best photo phones.

NB. This article was written as part of a press trip organized by Vivo to Berlin with Zeiss team.

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