Carbon 1 MKII Review – First smartphone with carbon fiber unibody

It was a clear message during the Carbon Mobile presentation of the Carbon 1 MKII: plastic, glass and metal are hell and old-fashioned. Carbon fiber is the future for smartphones. The technology is still in its infancy, but in a decade or so most phones will be made from this material. Thousands of interwoven carbon threads must ensure a housing that is stronger than steel and lighter than aluminum.

The innovative choice of materials goes hand in hand with the gründlichkeit of the German start-up, founder Firas Khalifeh said in person during the press presentation and Q&A. It’s something different from a slick show with a hired National Geographic photographer who talks about how good the camera of a new smartphone is, or an Asian CEO who reads a script in poor English. However, the innovation that the smartphone itself brings is more interesting, of course.

Light, thin and strong

The Carbon 1 MKII – to be pronounced as ‘mark two’ – has a housing that consists of one piece of interwoven carbon fibers. You probably know this carbon fiber from Formula 1, racing engines and the aircraft industry. The material is light, but very strong. Although we didn’t get to try it, in theory carbon fiber can withstand a fall better than metal – and certainly better than glass. It is more flexible than those materials and you feel that when you try to bend the device. He gives way, although we are not afraid that we will quickly break him in half. Something that yields slightly can, in principle, withstand impact a little better.

A complicating factor when using carbon fiber for a smartphone housing is that, like metal, it does not transmit radio signals. Carbon Mobile has solved that with a technology called HyRECM. The carbon fiber is mixed with other composite material in certain places, so that the antennas can do their job. These are probably the solid black spots below and above the part with the diamond pattern that is so typical of carbon fiber.

Holding the Carbon 1 MKII, you’ll notice how light a phone this size feels that weighs just 125g. The larger smartphones made of metal and glass are increasingly reaching 200 grams. However, you cannot really compare this device with that. A well-known device that comes pretty close, but is still slightly smaller, is the Samsung Galaxy S21. The Pixel 5 does have a similar screen diagonal, although the Carbon 1 MKII’s screen is slightly wider.

Device Galaxy S21 Carbon 1 MKII Pixel 5
Dimensions 151.7 x 71.2 x 7.9mm 153.5 x 74.0 x 6.3mm 144.7 x 70.4 x 8.0mm
Weight 171g 125g 151g
Housing material Metal and glass Carbon fiber Plastic
Screen diagonal 6.2″ 6.0″ 6.0″
Screen ratio 20:9 18:9 19.5:9
Screen resolution 1080×2160 pixels 1080×2400 pixels 1080×2340 pixels
Screen protection Gorilla Glass Victus Gorilla Glass Victus Gorilla Glass 6

The Pixel 5 is one of the lightest phones we reviewed last year. However, the Carbon 1 MKII feels a lot lighter. It is also a relief in the pocket, after all the heavy and large phones that we carried with us last year, despite the fact that the pockets of most clothing brands have grown along with the expanding smartphones. You hardly feel this phone from Carbon Mobile. This is of course partly due to the extremely thin housing, and that is also an advantage of carbon fiber: it does not have to be thick to be sturdy. The material also feels pleasant to the touch and, just like plastic, does not get very hot or cold.

It can be a bit slippery if you have dry hands, although that is the same story with glass. Another disadvantage is that it is less scratch-resistant than the various variants of Gorilla Glass that we encounter on smartphones today. We could easily cause a light scratch with a wrench. Also, some will associate the weight of the Carbon 1 MKII with being cheap and fragile. That is not a real disadvantage, but perception is simply a factor. The handfeel is somewhat reminiscent of the somewhat cheaper, plastic-made telephones from a few years ago. That idea could probably have disappeared with longer use if the rest of the phone would feel luxurious.

Unfortunately, the latter is not the case. The vibration motor is very weak, Android does not always run smoothly and the fingerprint scanner on the side of the device works quite slowly. That is ashame. If Carbon Mobile had focused a little more on these elements that greatly influence the day-to-day experience, the phone wouldn’t have to feel like a much cheaper device. Fortunately, the speaker does sound quite good and the maximum volume is very acceptable. However, it is a mono speaker, on the bottom of the device.

Not for the specs

For a smartphone of 800 euros, the Carbon 1 MKII is also poorly endowed on other points. As a small smartphone maker that purchases parts in limited numbers, you simply pay more and that is reflected in the retail price. Also, developing the carbon fiber technology has been a huge investment for the company. Carbon Mobile says it is open to licensing their intellectual property to other smartphone manufacturers. Moreover, there are already plans for the next own carbon fiber smartphone, with better specifications. However, that will take some time.

How mediocre are those specifications? First of all, the device has a Mediatek MT6779 Helio P90-soc . That is a not-so-high-end soc, made on TSMC’s 12nm FinFET process, which was in smartphones in 2019. The performance is slightly below that of the Snapdragon 765-soc, which was popular last year, you can put it succinctly. The device has no 5G, no telephoto, macro or ultra-wide-angle camera, no increased screen refresh rate, no supplied charger, no wireless charging and is equipped with Lpddr4X working memory and only UFS 2.1 storage memory.

However, it can certainly also be worse, because the storage memory is 256GB, there is 8GB of RAM, an NFC chip, an OLED screen and a USB-C port in version 3.1. There is also a waterproof rating, namely IP65. This means that the device is dust-tight and will not be damaged if it is sprayed at any angle with 12.5 liters of water per minute.

Android 10 is currently running on the device, although Android 11 will arrive in April if all goes well. Navigating Android is fine and the memory management isn’t too aggressive, but when scrolling through web pages, Gmail, or the Google Discover feed there are a lot of frame drops. It’s almost stock Android what runs on the Carbon 1 MKII. It does have its own launcher though. According to Carbon Mobile, updates are therefore very easy and quick to implement and the manufacturer offers monthly security updates.

Simple camera

The Carbon 1 MKII’s cameras aren’t plentiful in number. At the front is a 20MP camera with a Samsung S5K3T2 sensor and an aperture of f/2.2. There are two cameras on the back, one of which is intended to estimate depth for artificial background blur. Both have the same specs: a 16MP Samsung S5K3P9 sensor and an f/2.0 aperture with optical stabilization.

The photos that the Carbon 1 MKII takes are obviously not of the level that you shoot with a Galaxy S21. Unfortunately, you cannot expect a start-up to have its camera software as well developed as that of a manufacturer that has been optimizing it for years. Also, the sensor itself isn’t the newest and biggest. If you compare the photos with those of the Galaxy S21, it is especially striking that the Carbon 1 MKII takes less contrast-rich photos, with less detail and more noise. The automatic white balance is also not very accurate. Still, we can imagine that the photos from the camera on the back are still quite acceptable, if you’re not too picky. The front camera is unfortunately a lot less good. The dynamic range is limited and the colors are far from ideal. The portrait mode is also nothing to write home about.

Test results

Well, with the Carbon 1 MKII you don’t have the latest and best specs or the best camera, but at least it does have an OLED screen. We measured that with our SpectraCal C6 colorimeter and Calman 5 software.

The screen does not have a powerful brightness boost when bright light shines on it. As a result, the maximum brightness lags behind that of the other devices in this list. Nevertheless, we can usually read the screen well outside, as long as the sun does not shine directly on it. Then it becomes very difficult. The minimum brightness is a bit bright on the eyes if you are in a completely darkened room. In terms of color fastness, the Carbon 1 MKII also scores below average, although many people will not notice this. Due to professional deformation, however, we do see it, even without a reference.

Thin phones do not always have a large battery capacity and we also suspect that Carbon Mobile wanted to keep this phone as thin as possible to emphasize the advantage of carbon fiber. A battery of 3000mAh is quite scanty with a screen size of 6 “. We can see that in the battery results. They are below average for a phone from 2021.


Not entirely surprising: we do not recommend the Carbon 1 MKII to the average consumer. The specifications are scant for a phone of 800 euros, the battery life is below average and the camera is not great either. However, the Carbon 1 MKII, just like a Fairphone, is not just about specifications, performance and the money you put down for it. According to Carbon Mobile, the goal is to sell several tens of thousands of devices. That is not much and this first carbon fiber smartphone is mainly intended as a starting point and for now only interesting for the early adopter .

We have therefore omitted the scorecard, although it does receive a deserved Innovation Award from us. There are still many steps to take before more smartphones get a carbon fiber body. According to Carbon Mobile, the production process per smartphone housing has already been shortened from three hours to half an hour. That has to go much further down if major smartphone manufacturers are to become really interested in the option of equipping their smartphones with carbon fiber. Nevertheless, it is nice to see that innovation is still taking place with some regularity in the smartphone market. And if durability and a thin and light smartphone are important to you, along with the idea of ​​being at the forefront of technology, the Carbon 1 MKII might not even be such a crazy buy.