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Blackmagic 4K tests: battery life, data and record time

Updated July 20, 2014 to reflect the addition of more ProRes codecs in firmware update 1.8.2

I wanted to share my recent little study with other 4K Blackmagic Production Camera users (and potential Blackmagic users), so that we can better understand the battery drain of this camera. Here are some of the questions I have asked:

  • How long will the Blackmagic 4K camera record on the internal battery?
  • How big of an impact does screen brightness have on battery life?
  • Does 4K resolution drain the Blackmagic camera’s battery more quickly than 1080p resolution?

I performed a series of tests where I charged the camera to 100% battery, unplugged it, hit record, and let the camera record until the battery died. I then removed the SSD and mounted it on my computer to see the clip’s duration and file size. Here are the results:

Blackmagic 4K Production Camera Battery life

All tests at 400 ASA, 180 degree shutter angle, 23.976 fps
CodecResolutionBrightnessRecord Duration
ProRes HQ1080p065 minutes
ProRes HQ1080p10055 minutes
ProRes HQ2160p067 minutes
ProRes HQ2160p10059 minutes
It’s fascinating to me to see the following:
  • 4K resolution drains the battery more slowly than 1080p resolution
  • 100% screen brightness only drains the battery 12-15% more quickly than 0% screen brightness

My guess is that the sensor is natively 4K, so the in-camera processor needs to work less than when scaling/debayering the image down to 1080p, therefore drawing less from the battery due to the decreased processor activity.

Also, here are the stats that my tests demonstrated regarding how large a 4K or 1080p clip can be expected to be, as well as how much time I can expect to fit on a 480 GB SSD drive:

Blackmagic 4K Production Camera file sizes and data rates

Note: All codecs with variable bit rate (VBR) will yield slightly different results depending on picture content and how it is compressed. Footage with more detail or movement will take up slightly more disk space.
 CodecResolutionFile size (GB/min)Data rate (mbits/sec)Minutes on 480 GB
1ProRes Proxy1080p0.2738.601778
2ProRes Proxy2160p1.03148.63466
3ProRes LT1080p0.5984.11813
4ProRes LT2160p2.31331.39208
5ProRes 4221080p0.83120.22578
6ProRes 4222160p3.31474.85145
7ProRes 422 HQ1080p1.25178.29384
8ProRes 422 HQ2160p4.95709.1197
9CInemaDNG2160p12.19167039

I hope this is helpful to someone out there! Please leave a comment if you have any questions or anything to add to the discussion!


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