Xiaomi Yi II 4K Action Cam Review
Forget about poor quality spherical videos from a pair of ugly sunglasses that you can only purchase from a travelling vending machine . To really share the exciting bits of life, you should use an action cam.
But getting good quality action cam footage – particularly in 4K resolution – has been prohibitively expensive. Until now. The Xiaomi Yi II is a 4k capable device for less than $300 that does everything you want it to, and more. In fact, it’s better than the equivalent (and more expensive) GoPro models. Seriously.
The Yi II features a fixed F2.8 lens with 155° field of view. Inside you’ll find an Ambarella A9SE75 processor, Sony IMX377 image sensor (the same as the Nexus 6P phone), and a BCM43340 dual-band Wi-Fi module. Power is provided by a 1,400mAh replaceable battery, and the whole thing weighs around 90g with the battery inserted.
On the rear is a 2.2″ touchscreen, providing easy access to the settings and a useful viewfinder.
A huge range of recording modes are possible, all the way from 4K 30FPS (frames-per-second), to 720p 240FPS:
- 4K Ultra (3840×2160), 30 FPS (this uses around 60MB/s, so just over an hour of recording on 32GB card)
- 4K (3840×2160), 30 FPS
- 2.5K (2560×1920), 30 FPS
- 1440p (1920×1440), 30 FPS / 60 FPS
- 1080p Ultra (1920×1080), 30 FPS / 60 FPS / 120 FPS
- 1080p (1920×1080), 30 FPS / 60 FPS / 120 FPS
- 960p (1280×960), 60 FPS / 120 FPS
- 720p (1280×720), 240 FPS
- 720p Ultra (1280×720), 60 FPS / 120 FPS
Ultra modes all use about a 50% higher bit rate, but otherwise I couldn’t detect a difference in frame size or field of view. All are output as h.264 .mp4 files. A good rule of thumb is always to record in the highest quality you can afford to given your storage capabilities (same for photography: always use the highest quality, RAW output ). This gives you the greatest flexibility when editing. For instance, if your final output is 1080p, you should still record at 4K anyway so that you have some buffer room to cut and frame later without sacrificing final resolution. You can also take photos at 12 megapixels (you can see some samples in the video), but this probably isn’t why you’re buying an action camera.
In terms of shooting functionality then, it’s roughly equivalent to a GoPro Hero 4, which retails at twice the price; but the Yi 4K also includes a touchscreen, and a slightly longer battery life.
The Yi 4K doesn’t come with any accessories though, so do remember to factor in the cost of a waterproof case, high speed micro-SD and any suitable mounts you want. The good news is that once you’ve purchased a case, it’s more than likely to be compatible with any GoPro mounts you might have. This is the case I picked up for about £10:
Note that there are two version of this device floating around: the domestic Chinese version, and the international version. The international version appears to have a slightly higher framerate (30fps vs 25fps baseline), but slightly smaller battery. The domestic version was also apparently plagued with stuttering issues, and users complained of the lack of English instructions. If you’re reading other reviews before October 2016, they most likely refer to the domestic version. I didn’t experience any stuttering of videos, having used a number of class 10 Sandisk microSD cards for recording.
One ever so minor complaint that I have is that the micro-SD card is tucked away underneath the battery, so it’s a little awkward to remove.
Built into the back of the device is a brilliant little touchscreen that’s both responsive, bright, and uncluttered. Unlike cheaper devices, it doesn’t feel like a constant battle to get touches recognised, and the menu interactions are smooth and easy to access.
A lot of the time, when the device is strapped on and in a case, you’ll be using the Wi-Fi remote link and the app – but it’s certainly nice to have a screen on the back for times when you can access it.
Wi-Fi Remote Control
An obvious feature for a camera that may spent its life locked away in a waterproof and mounted to an awkward position is that of Wi-Fi control. Thankfully, I found it to be rock solid. The range is about 25-30m outdoors, and even when you get disconnected by moving out-of-range, your smartphone should automatically reconnect when it comes back, and the app will pick up where it left off. The recording continues even without an active Wi-Fi connection – you just won’t see the preview until you move back into range.
The app itself is relatively easy to use, once you’ve opened up the remote control screen. By default, it opens to an Instagram-like stream of footage, shared by other users to the app. I can’t say I spent much time there, given that browsing random people’s travel photos is about the most boring thing I could consider doing.
Electronic Image Stabilization
Some modes enable the use of EIS (Electronic Image Stabilization), a built-in algorithm for stabilizing footage. It works by reducing the field of view slightly, thereby creating a buffer around the frame, with the result of less shaking. Video modes that support this don’t appear to be documented, so it’s trial and error when selecting them. For instance: neither of the 4K modes support EIS, but the 2.5K mode does; 1080p 60fps Ultra doesn’t, but regular 1080p 60fps does.
That said, it isn’t a feature that you couldn’t otherwise achieve in post with most video editor software, but if you don’t want to deal with video editing afterwards then it’s certainly cool to have this on the camera itself.
One of the great things about having a chip inside the camera that’s capable of the bit rates required to record 4K footage, is that it can also record at a lower resolution, but faster. In other words, you can record at up to 240 frames per second if you’re willing to drop down to 720p, giving you the opportunity to slow the footage down 8X and still maintain a fluid frame rate for 30fps video output. You can see samples of this in the review video.
Quick tip: selecting the Video mode and then choosing 720p/240fps from the settings menu is different to choosing Slow Motion mode from the quick mode select menu. The Slow Motion preset will automatically output the entire video at 30fps, but slowed down. If you’re editing the videos, you’ll want to skip that, and choose regular Video mode but at a higher frame rate, in order to have more control over the quality and re-timing.
Another fun feature of the Yi 4K is the time lapse mode, in which you set the interval and time, and camera spits out a video at the end. Sadly, this is limited by the battery, so you’ll get about 80 minutes worth. You can’t simultaneously charge the battery and use it at the same time.
On the day of publishing this review, the camera’s firmware was updated to allow live streaming. Unfortunately, the mobile app doesn’t appear to be updated yet, so we were unable to test this feature. However, this is how it’s supposed to work: use the usual Facebook or YouTube live streaming configuration page to generate a stream URL containing the secret key (single URL style, without separate authorization keys). Copy the URL into app (this is the bit we couldn’t test). Then scan the QR code generated by the app with the camera. The camera starts streaming to URL specified. We’ll update the review once we’ve been able to test this.
Stated life of the 1400mAh battery is about 2 hours, which lined up with my experience. This is almost double that of the GoPro Hero 4.
The batteries is removable, replaceable, and inexpensive. You can purchase a pack of 2 third party spare batteries and charger for $15 on Amazon.
Should You Buy a Yi II 4k Action Cam?
It’s rare to find a Chinese knock-off that’s just as good (if not better) as the market leader, but the Yi 4K genuinely is. Not only is it cheaper than the equivalent GoPro Hero 4, it also boasts a longer battery life, and a touchscreen on the back. If you’re in the market for an action camera, buy the Yi 4K.
For half the price of the leading competitor, the Yi 2 offers a longer battery life and touchscreen viewfinder. This IS the action cam you’re looking for.