digital zoom testing with different resolutions
781 3 2020-11-19
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djiuser_spQ2qqa7fqnT
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Canada
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I have been playing with my pocket 2 for 1 week. I noticed that the digital zooms are only lossless with a limited amount of zoom and the lossless zoom range depends on the resolution, here are my findings so far

1080p 60 frames 1.9x zoom (lossless)
1080p 60 frames 2x zoom (almost lossless)
1080p 60 frames 3x zoom (degraded)

1080p 60 frames 4x zoom (degraded)

2.7k 60 frames 1.4x zoom (lossless)
2.7k 60 frames 1.5x zoom (almost lossless)
2.7k 60 frames 2x zoom (degraded), the 1080p 2x zoom footage has more detail

2.7k 60 frames 3x zoom (degraded)

4k 60 frames 1.2x zoom (slightly degraded)
From the results, It seems that pocket 2 captures the footage in native 4k and downsamples to 1080 or 2.7k.  But I may be wrong...
Anyone else noticing this?

Ping-Huan
2020-11-19
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Cients
Second Officer
Flight distance : 5537369 ft
Portugal
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Nice tests
2020-11-21
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djiuser_spQ2qqa7fqnT
lvl.1

Canada
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Got some feedback from DJI and it confirms my testing results:

The Pocket 2 zoom is digital zoom which is cropped from 4.6K video so this is normal. when zooming, there is a lossless zoom and a digital zoom. Thank you for understanding.
2020-11-22
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CemAygun
Second Officer
Flight distance : 810 ft
Philippines
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Thanks a lot for the tests, this was really important. The part I was most curious about was that if they would use the un-binned, full sensor readout data. That would have given an insane amount of lossless zoom, albeit the color being highly interpolated (as the color filter only has 1/4th the resolution).

But the results are kind of baffling for me. A 1080p readout should at least have a perfect 2X zoom out of a 4K capable sensor (around 8MP at 16:9, and 12MP at 4:3) which is exactly what happens with Pocket 1 when it uses the slow motion mode. Since the Pocket 2 sensor is denser at 16 MP (4:3) even when binned, it should have a better, "non upscaled" zoom range at 1080p.

And 2.7K resolution should be good up to 1.7X zoom to reach 4.6K resolution claimed by DJI.

In the end my calculations are all on paper; they are what simple math dictates. Unfortunately they do not always translate well into real world applications...
2020-11-22
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