Report on the Yi 4K+ - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 12 Old 08-14-2017, 09:18 AM - Thread Starter
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Report on the Yi 4K+

The Yi 4K+ uses a new processor. It has four advantages due to its being more powerful and more energy efficient:

1. One can now shoot UHD (4K) video at 60 fps.
2. One can shoot UHD at 30 fps with EIS that is very sophisticated and digital fisheye correction in camera (no crop).
3. Battery life is longer.
4. No overheating.

Why do we care about 60 fps? Actually, I can never detect the difference between video shot at 30p and 60p. The key advantage is that you can slow down the video and still have 4K, using 30p as the rendered video.

Why is slowing down useful? You can smooth out camera moves - it smooths out pans and, most importantly, smooths moving with the camera (on a gimbal) - and subject action slowed down makes that action more interesting.

I decided to test out this new camera, taking advantage of its 60p in 4K. I had a gimbal, so I could move with the camera (it also produces motorized pans). To achieve the minimum weight (125 grams) for the gimbal (Feiyu Crane M) I put the camera in its waterproof case. So, I was going to shoot on the beach, temperature over 80 degrees (F) sealed in an airtight case! Will it overheat?

The results:

1. I shot for a period of 1 hour 31 minutes, never turning off the camera in the hot sun, until the battery ran out (first charge). That is much longer battery life than any small camera I have ever used.

2. I shot 50 minutes of “footage” taking up 51 GB’s on the micro sd card (135 Mbps bitrate) during that time.

3. No overheating - again, the camera was on the whole time, and 55% of the time the camera was recording. No other small camera I have used (Sony RX100 IV, GoPro Hero 4 Black and Hero 5, Samsung 360 Gear, Kodak 360 4K) could do that, not even close. Now, overheating can shut the camera down or it can cook the sensor (hello, GoPro and Kodak and Samsung), resulting in low-resolution results. Neither happened.

And here is the edited 4K video, shot on the gimbal - with smooth slowed pans, and slowed moving with the camera and static shots, some slowed. You are seeing 4K, a dynamic video and slow motion!


Now, what about using the camera without a gimbal? How good is the EIS in 4K (30p) in eliminating shakes? Here is the 4K test video, all handheld (static shoots).


Pretty amazing, and I do not see much loss (if any) in resolution. Handheld, 4K, tiny camera - better than the Sony BOSS.

Last edited by markr041; 08-14-2017 at 07:21 PM.
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post #2 of 12 Old 08-14-2017, 06:26 PM
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Any option to shoot in a rectilinear format at either 4K/60p, or 4K/30p + EIS? The older Yi 4K can do it at 4K/30p but without EIS.

I understand the need to have this widest possible view (from near 180° fisheye to around 120° with a crop in 4K/30p + EIS?) as the purpose of any action camera is first and foremost, unmanned shooting. But if they can offer a choice of non-distorted optics for these cameras, many traditional shooters would buy it without hesitation at these ridiculously low price points. Great image, extremely compact, minimal fiddling, what's not to like?
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post #3 of 12 Old 08-14-2017, 06:52 PM - Thread Starter
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Quote:
Originally Posted by P&Struefan View Post
Any option to shoot in a rectilinear format at either 4K/60p, or 4K/30p + EIS? The older Yi 4K can do it at 4K/30p but without EIS.

I understand the need to have this widest possible view (from near 180° fisheye to around 120° with a crop in 4K/30p + EIS?) as the purpose of any action camera is first and foremost, unmanned shooting. But if they can offer a choice of non-distorted optics for these cameras, many traditional shooters would buy it without hesitation at these ridiculously low price points. Great image, extremely compact, minimal fiddling, what's not to like?
Yes! In 4K 30p with EIS on you can choose distortion correction, which gets rid of any fisheye distortion - this is NOT a crop of the sensor. This is the same technique Sony (and others) use in their top cameras with their E lenses, some of which have severe optical barrel distortion, for example, which is digitally corrected in the camera. For video and jpegs this distortion is eliminated (but not RAW). I did not use it in the 4K 30P with EIS video I posted.
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post #4 of 12 Old 08-14-2017, 07:02 PM
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Great. Time to get one myself. The only problem is though the camera has been available for quite some time in the grey market including Amazon and eBay, it still had not been on sale in my region with full local distributor warranty. Maybe the new chip has been in short supply or something but hopefully the wait won't be too long.
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post #5 of 12 Old 08-14-2017, 07:26 PM - Thread Starter
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Quote:
Originally Posted by P&Struefan View Post
Great. Time to get one myself. The only problem is though the camera has been available for quite some time in the grey market including Amazon and eBay, it still had not been on sale in my region with full local distributor warranty. Maybe the new chip has been in short supply or something but hopefully the wait won't be too long.
I acquired it from Amazon, who is distributing the camera on behalf of Yi. It came in one day (free shipping, no tax), and I even got an e-mail from Yi thanking me for the purchase. So, no grey market, and it must be warehoused by Amazon. Yi also sells directly from their US web site. I think many producers now just use Amazon to service their sales.
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post #6 of 12 Old 08-15-2017, 02:27 PM - Thread Starter
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In-Camera De-Fisheye Demonstration - 4K


This was handheld, using the in-camera stabilization (still rock solid). First shot is without the correction, second with it turned on.

Other notes:

1. Transfer speed of clips on the sd card in the camera to the computer is 40MBs/s, as opposed to 20 MBs/s on all my other cameras. This is because of the USB-C port. When you are transferring 51 GBs of 135Mbps video files, this matters.

2. Yesterday, Yi issued another firmware update, which "Optimized image quality, improved the image contrast" as well as some other minor stuff. Most of the firmware updates have increased functionality (adding livestream, 24p, RAW time lapse, % battery life indicator, shutter speed choices).
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post #7 of 12 Old 08-15-2017, 08:51 PM
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Quote:
Originally Posted by markr041 View Post
Actually, I can never detect the difference between video shot at 30p and 60p.
Really? I can see the difference right away. I cannot say whether it is exactly 30fps or 60fps, but the difference in motion is obvious to me.
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post #8 of 12 Old 08-16-2017, 12:25 PM
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Good to see they added 24p. If the lens is unscrewable then it should be fairly easy to replace it with a flat lens of 70 degrees. I did that with an inexpensive 4K camera. The lens was only $10 including shipping out of China and arrived in about a week.
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post #9 of 12 Old 08-16-2017, 06:22 PM
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If that lens is as good, i.e. has the same level of aberrations, as the original fisheye lens on the camera then we could probably witness the best bang for the buck for a video camera at that combo price!

The only catch is as far as I know the original lens is fixed-focus so it would be interesting to see how you would optimize the focal point on the new 70° lens. The hyper focal distance has to be significantly far off from the fishehe lens if it's designed to ensure adequte focus at the infinity.
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post #10 of 12 Old 08-16-2017, 09:02 PM - Thread Starter
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And of course it does time lapse 4K (from 4:2:2 jpeg and Raw)

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post #11 of 12 Old 08-17-2017, 11:09 AM
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Quote:
Originally Posted by P&Struefan View Post
If that lens is as good, i.e. has the same level of aberrations, as the original fisheye lens on the camera then we could probably witness the best bang for the buck for a video camera at that combo price!

The only catch is as far as I know the original lens is fixed-focus so it would be interesting to see how you would optimize the focal point on the new 70° lens. The hyper focal distance has to be significantly far off from the fishehe lens if it's designed to ensure adequte focus at the infinity.
I used the camera's HDMI output to focus the replacement lens. It would only output 1080p live but that was sufficient for it's 4K focus. Here's a video by someone installing a flat lens on a Yi 4K camera. My install was even easier as I only had to remove the guard around the lens which just twisted off and unscrew the lens and screw in the flat lens.
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post #12 of 12 Old 08-20-2017, 01:47 PM - Thread Starter
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I shot a RAW Video with the Yi 4K+

In time lapse mode, one can choose to make 12-megapixel RAW images (+ jpegs). This was shot at night using a 5-second shutter and ISO 200 to capture light trails. The camera was shooting for 2 hours and 40 minutes. There are no limits on number of images. The battery had run down to 20%. The 605 RAW images were converted in Lightroom to 4:4:4 jpegs and then assembled in Vegas Pro.


You can stop this video on any frame and see the detail and lack of noise. WB was set in Lightroom so that the street light color matches exactly what the street lights give off. I set the exposure in Lightroom to match what the eyes see.

Last edited by markr041; 08-20-2017 at 02:35 PM.
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