If you were thinking smartphones can’t get any cheaper, have a look at the Cubot Rainbow 2. At a price of less than 70$, Cubot tries to lure smartphone beginners and mad savers. It is surprising that the phone houses a dual-camera. In other points, however, the manufacturer economized. For instance, you only have 1GB RAM and a budget-processor available. LTE is not supported at all. If the dirt cheap 5-inch smartphone is of use, you’ll find out in the following review.
Build quality and Design
The Cubot Rainbow 2’s design is not very rash; it is best described as a “simple, but fine” smartphone. The dimensions of 144 x 72 x 7.9mm make it possible to use the phone with only one hand. The smartphone’s haptics are also nice. The rounded-off edges as well as the slim design make it comfortable to holding the phone in the hand. It feels good and you don’t have to worry about the smartphone slipping out of your hand. The weight of 155g is an average value. I definitely can rule out cramping hands and sore muscles for the average user.
Only when you hold the smartphone in the hand, you notice that the aluminium frame is actually not made of aluminium. Unfortunately, it is only made of plastic, as are power button and volume control. Despite the material, they are fixed well in the casing and have a nice feedback. The position of the micro-USB port is quite unusual, as it is located at the top next to the headphone connection. In daily use, we found it to be an advantage. The cheap hand-held computer could also be operated well if it was charged and you used headphones simultaneously. You don’t have the problem that a cable at the bottom hinders the operation.
The rear side is made of plastic, like the frame. According to the manufacturer, the high gloss back cover has a layer of paint that is resistant to fingerprints and scratches. At least, I did not find any scratches after the test period (however, I treated the phone carefully). Touching the phone on the other hand, clearly leaves fingerprints. The dual-camera juts out a little bit and it is surrounded with a fine, silver frame. The back cover is removable. Beneath, you find two SIM slots and one SD-card slot. The battery, however, is not replaceable.
The front side is completely covered by glass that is rounded off at the edges. Below the display, you can find three soft touch buttons, which are not illuminated. A blue notification LED informs you about missed calls or other notifications.
The Cubot Rainbow 2 is not available in all colours of the rainbow, but the colour option is something to be proud of. You can choose between gold, red, blue, black and white. The hardware is the same in any of the five versions.
Cubot Rainbow 2 scope of delivery
Besides the Rainbow 2, Cubot puts a micro-USB cable and a charging adapter in the box. On the display, a screen protector is fixed ex works, which is very kind of Cubot. Everyone who has already applied one by themselves knows hard it can be (especially for perfectionists). In addition, you get TPU-cover, which is made of a plastic-silicone-mix. The material is known for its robustness and durability.
There is a quick reference guide as well.
The Cubot Rainbow 2 houses a HD-display (1280x720pixels) with a pixel density of 294ppi. It is sufficiently sharp, so that you can enjoy multimedia contents in any case. It is noticeable that there is a visible gap between the 2.5D glass and the IPS panel. The display does not seem to be stuck together with the glass. This is a disadvantage, especially in terms of reading in bright sunlight. Despite a high display brightness, it is hard to read contents when the sun shines directly on the display. Viewing angles on the other hand are stable and colour representation is nice. Contrasts could partly be a bit stronger. Thanks to MiraVision, the depiction of contents can be customized. If you adjust the settings according to your own preferences and do not use the standard configuration, the display can be really good.
Unfortunately, the rainbow-smartphone does not use Gorilla Glass. Those who want to prevent scratches should use a screen protector in any case or rather not remove the already fixed protector. You can wake the phone up by tapping on the display. The Cubot Rainbow 2’s extraordinary multitasking ability is surprising. It can register up to 10 points of contact at the same time, which are also recognized reliably. In contrast to many other low-budget phones, the Rainbow 2 can be operated reliably at any time and is therefore suitable for those who write a lot.
All in all, Cubot gave the Rainbow 2 quite a nice display for a phone in the ultra-low-budget sector. You should not expect a full-HD display in this price range.
In terms of performance, there is nothing to complain about in daily use. Navigation through the menu happens fast, apps are loaded quickly and there are no jerks when scrolling. This is thanks to the budget-processor MediaTek MT6580A with four 1.3GHz cores. This processor, in combination with a Mali 400 GPU, does not give a masterly performance of games like Asphalt 8 or Modern Combat 5. Only one 3D game, NOVA 3, could be played fairly fluently. Less demanding games like Mario Run are really fun on the smartphone. You couldn’t have expected more. The Antutu benchmark of 24,500 points (below the average) is therefore not a surprise. Heat development is okay. The Rainbow did never get too hot. Only when the device is being used or when the battery is charged you notice a clear heating up of the rear side.
Cubot provides the feature “DuraSpeed” in the settings, which terminates background processes in order to secure the maximum of possible power for the currently active application. As the RAM is rather small (1GB), only a small amount of processes and apps can be carried out at the same time. A performance test of the storage showed results below average. The RAM’s speed of 1.5GB/s is really nothing to be proud of. The internal flash-storage is not fast either. The reading/writing speed of 30-40MB/s is extraordinary (in the negative sense).
Overall, the Cubot Rainbow 2 provides enough power for using basic functions such as surfing, watching videos or occasional gaming. Only when playing high demanding games, there are some problems with the performance.
Rainbow with Nougat (Android 7)
The Cubot Rainbow 2 has the latest Google operating system. The system has barely been changed. Therefore, nobody should have any problems to get along well. In the settings you can find the item “parallel space”: a genius tool, which allows cloning apps. This brings along some advantages, e.g. it is possible to install WhatsApp twice, so that you can use the messenger with two phone numbers, if two SIM cards are used. Further, you can create two profiles in online games via the parallel space (e.g. Clash of Clans or Clash Royale). This makes it possible to use two accounts on the same device.
I discovered another small feature in the system by chance: if you swipe up on the home screen, quick links to the most used apps and settings for Wi-Fi, Bluetooth and display brightness appear. This function reminds me of the quick-settings toolbar by IOS.
In addition, there is a multi-user function available, with which you can create a guest account with restricted permissions, if you lend your phone to somebody else.
The system runs fluently and without crashes. Cubot made a smart decision choosing Android 7. The operating system should stay up-to-date for the next months. Updates are installed via OTA.
Let’s get to the feature which makes the Cubot Rainbow 2 something special: the dual-camera. Cubot sees two advantages in using two camera lenses (13MP + 2MP): on the one hand, you should be able to determine the distance between certain objects, on the other hand you should get twice the speed thanks to two apertures. The former should blur the non-focused objects in the background, in order to increase spatial perception and give priority to the focused object. So much for theory. In daily use, however, the Cubot Rainbow 2’s dual-camera seems not to work too well (so far). The ‘blur effect’, as it is called, focuses only an oval area around the focused point, but does not pay attention to spatial distance. To achieve this effect, a dual-camera is not necessary. Maybe a future update can bring a more useful ‘blur effect’.
The manufacturer states an aperture of f/2.0. According to Meta data, however, all images were taken with an aperture of f/2.4. Unfortunately, I’m not able to tell for sure which one is the right value.
Apart from that, the camera takes quite nice pictures, which are also represented sharply on a 15.6-inch laptop screen. Zooming in, the picture gets easily grainy. Colours are not distorted, but they sometimes seem a bit pale. The trigger is quite slow and the autofocus has some problems sometimes. The camera has difficulties in finding the focus in bad lighting conditions especially. At night, the camera is rather useless. As soon as there is less light, image quality decreases rapidly. In order to get reasonable pictures at night, there has to be a lot of artificial light. The double speed through two lenses is not noticeable.
Pictures taken with the rear camera are sharp, a fact which is not true for the front camera on the other hand. It has only a 5MP resolution. However, even this information seems unrealistic to me, given the grainy pictures. There is only one possibility to take detailed selfies with the Cubot Rainbow 2: you have to turn the smartphone around, use the volume down button as trigger and hope that your face is in the focus.
Why the front camera has an LED-flash remains a mystery to me. The manufacturer should have rather built in an appropriate sensor instead wasting money on such knick-knacks.
Those who expect the Cubot Rainbow 2 to have a high-end dual-camera as current Huawei smartphones will remain disappointed. However, the camera is appropriate for the price range.
The probably weakest point of the Cubot Rainbow 2 is the missing LTE module. The smartphone only supports 2G and 3G, but not 4G networks. The networks available are sufficient for surfing and telephoning, but those who love mobile internet will not be happy. Nevertheless, reception is very reliable. The smartphone supports at least dual-SIM and you can also expand the storage via a micro-SD card (up to 256GB). Luckily, Cubot did not use the hybrid-solution in this device, which allows you only to use storage expansion or dual-SIM, but not both.
When telephoning, voice quality is sufficient. The speaker on the other hand is bad. The caller hears himself twice as soon as the speaker is used. In addition, it is a struggle to listen to the caller, as the speaker sounds extremely tinny at higher volume. We recommend telephoning in the conventional way, i.e. holding the phone to your ear. Doing this, voice quality is significantly better.
When it comes to listening to music, the speaker cannot convince either. The sound is too shallow and gets even worse with higher volume. The speaker is only suitable for watching videos or gaming. Using headphones is possible, thanks to the AUX port. There is also a Bluetooth 4.0 interface for wireless headsets or data transmission. NFC is not available on the reasonable Cubot smartphone.
In terms of Wi-Fi reception, the Cubot Rainbow 2 can convince. It can receive only the 2.4GHz frequency, but in a good quality. The connection to a wireless Access Point is also stable when passing walls. In contrast, the GPS module seems to be not to too reliable. The right position can mostly be found, but in navigation, the determined position sometimes moves along even if the car is parking, or the position is put into a parallel street. Therefore, the low-budget device is only partly suitable for replacing a navigation system.
Concerning sensors, the multifunctional device provides the standard. There is a brightness sensor to automatically adjust display brightness. Moreover, there are also a proximity and an acceleration sensor available. Fingerprint scanner, compass and gyroscope are not included.
A 2350mAh battery is nothing special. However, don’t forget the almost minimalist hardware, which will probably not consume much battery. This was also confirmed in the test. The battery lasted easily for one day, although the device was pushed to its performance limit with several benchmark tests. During normal use the device lasts for 1- 1.5 days before you have to charge it.
It took the PC-Mark battery test 6.5hours to reduce the battery from 100% to 20%. This is quite a good value. However, quick-charge is not available. It takes the battery 2 hours to reach 75%, and the phone is fully charged after 3 hours. However, as smartphone are mostly charged overnight, this should not be a problem.
* Incl. VAT and, if applicable, delivery costs – subject to interim changes.