A Day with the Huawei Mate 30 Pro: Kirin 990 and 7680 FPS Slow Motion Testsby Dr. Ian Cutress on September 23, 2019 4:00 AM EST
Huawei’s Mate 30 Pro: Testing 7680 fps Slow Motion
One of the headline features of the Mate 30 Pro is its super slow motion capabilities. Most smartphones available on the market today, if they offer slow motion, do it at either 120 fps, 240 fps, or up to 960 fps. This typically comes in the form of a sensor and system that can take 120 frames per second video and do clever interpolation to appear as if it is a higher frame rate. We’ve seen some good and bad solutions here.
The way that traditional slow motion cameras work is on a sliding scale – the trade-off between frame rate is resolution. If you reduce the area of the sensor that needs to take the image by one quarter, then technically the fast memory storing the video data can store 4x as much – as long as you can poll data from the sensor at 4x the speed, it should be good to go.
It seems that Huawei is doing a mix of things here to get 7680 fps. The camera offers several settings, which comes with a slider from 2x to 256x. Any setting 32x or lower gives a 1080p video, while 64x and higher gives a 720p video:
- 1080p at 120 fps = 4x speedup
- 1080p at 240 fps = 8x speedup
- 1080p at 960 fps = 32x speedup
- 720p at 1920 fps = 64x speedup
- 720p at 7680 fps = 256x speedup
There are no graduations in between. At 4x and 8x, users can take as much video as they want, and extend it all into slo-mo, but for the 32x speedup and beyond, the system will record a certain amount of video and slow it down. At 32x speedup, the video is 16 seconds, essentially recording 0.5 seconds of video. At 64x, the video is 32 seconds, recording 0.5 seconds of video. At 256x however, the video is also 32 seconds, meaning that the sensor can only record 0.125 seconds of video. It is worth taking that into account.
The other thing with slow motion video on this scale is light. The thing being filmed has to be illuminated sufficiently in order to get full detail. For anyone going around with 7680 fps photography on the brain, carrying a strong LED light for those dark areas of existence is probably worth the effort.
So here I’m going to show three videos taken with the Mate 30 Pro. This first video is the camera in 1080p mode, recording at 960 fps. This is what most high-end smartphone cameras can do.
Here we have a steady set of bubbles being created from the stream of water.
Now we can slow that down to 7680 fps.
Those first drops of water can accurately display the ripples from the spoon. One thing to note here is that with a smartphone camera, getting the thing to focus correctly while also holding a light is a right pain. That’s partly why the water stream is a bit out of focus in our close up shot. In the continuous stream section, we have some super slow motion water.
This third video was taken outside, and the simple act of dropping a leaf on a windy day.
If anything, 7680 fps here is too slow. Again, the focus plays a role here, and without a manual lens it is quite difficult to get it right for the shot as a whole. We can see the cyclist in the background slowly peddling through the shot, but we have lost detail on the leaf itself.