Any reports on using the 8X Zoom with either the Pro or Plus.

Discussion in 'SJ8 Series' started by karjak, Jan 26, 2019.

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  1. karjak

    karjak New Member

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    I have a SJ8 plus that is currently being shipped. Both the Pro and Plus have 8X zoom function but I now understand that SJCAM claims it is better with the Pro. Anyone have any opinions if the Zoom on the Pro would be significantly better?

    From ad on the SJ8 Pro 8X DIGITAL ZOOM

    See the miraculous work
    of Ambarella processor and Sony
    Sensor IMX377 combined.

    Clean image
    even after 8x magnification.



    zoom.JPG
     
  2. Sulev Svilponis

    Sulev Svilponis Elite

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    I don't have a SJ8Pro, so can't compare these cameras directly. But I uploaded a sample series for SJ8Plus, if you are interested.
    Images are jpg-s packed into zip folder. I hope that file names are self explanatory. If you zoom in the camera, then only JPG is recorded even if the RAW mode is ON.
    https://www.upload.ee/files/9483035/SJ8plusZoom.zip.html
     
    Last edited: Jan 27, 2019
  3. karjak

    karjak New Member

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    Thanks so much for sending the images. I just got the Plus and have done some quick checks inside taking pictures using Zoom. Your upscaled Raw 6X jpeg looks better than the Max zoom jpeg. Did you see any indicators on screen to show Zoom level? I don’t think it quite makes 8X zoom at max do you?

    I also don’t have a Pro to compare with. I did try to compare with my LightDow UltraHD (fake 4k) with inside videos. Lighting was bad but I took a video with the Lighdow maxed out to 4X looking at the refrigerator. I then took video with SJ8 plus and tried to match the image area by Zooming. I then took screen captures using VLC. At 4X the SJ8 looks somewhat better but not that impressed. What was your opinion? I really want to know if the Pro 8X digital zoom is all it’s hyped up to be.
     
  4. Sulev Svilponis

    Sulev Svilponis Elite

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    My SJ8Plus does not show any numeric indicator of the zoom level. According to my comparision, the max zoom is almost equal to the 6x upscaling (sizewise). SJ8Pro has some features that are missing in Plus, therefore, without having it, I can't say anything about it's zooming abilities.
    BTW, I did my upscaling after I converted the raw into jpg. I think, that this might be the reason, why the upscaled image is softer. Max zoomed directly out of camera jpg is definitely sharper, but also a lot noisier. I suspect, that the GIMP uses some antialiasing filter at upscaling.
     
    Last edited: Jan 29, 2019
  5. karjak

    karjak New Member

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    Thanks for the info. That is what I saw also. The zoom maxed out gave a really noisy picture, definitely not a "clean image". So upscaling with your GIMP software to 6.5X actually gave a nicer picture even though sharpness was less. I hope someone can provide some comparison between the Plus and Pro. Evidently the different processor is capable to run special software with the Pro to give a cleaner image with it's digital zoom. I took screen measurements of objects from your pictures and also of my of my own. I only get 6.5X at max zoom and not 8X.

    Taking video shots and using digital zoom during recording is what I am hoping will provide good results for me. As far as I know this Is the first action cam to offer a digital zoom with "real" 4K recording. The Pro can do 4K at 60fps where the Plus is limited to 30fps. Their are quite a few with digital zoom like my LightDow 4K UltraHD, that have interpolated or "fake" 4K recording.

    I want to use this camera attached to a spotting scope to take both videos and pictures. I need the zoom to eliminate vignetting. Even at 3.5X I should be able to eliminate most vignetting in videos and then use Handbrake or Avidemux to downscale the 4K to a get a HD video without black edges.
     
  6. Sulev Svilponis

    Sulev Svilponis Elite

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    I have only few experiences with upscaling, because I usually don't do that. Therefore the softness was possibly caused by my lack of knowledge, how to apply proper unsharp filter after upscaling. I did a new try with the unadjusted result from the raw image, and got better sharpness.
    https://www.upload.ee/image/9493247/6_6xUpscaledNoAdjustmentRAW.JPG
    This time I enlarged it exactly 6 times, and the magnification is larger than of max zoom from the camera. Hence, according to my tests, the max zoom is slighly less, than 6 times, not 6.5 times zoom.
     
    Last edited: Jan 30, 2019
  7. karjak

    karjak New Member

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    Got you on the Zoom. Meant to say 6X when referring to your upscaled image. I think I was being generous on my own measurements that max digital zoom is 6.5X. Definitely not 8X. Then again have to remember this is not physical and maybe a software upgrade could bring it up to 8X. But who would want something this noisy? Might be limited by the processor on how clean it can digitally produce.

    Having buyer’s remorse on purchasing the Plus. I am thinking the Pro digital zoom must be significantly better if ad claims are true that it gives: "Clean image even after 8x magnification".

    Perhaps the digital zoom works better in recording video. This must be quite processor intensive to do this in real 4K. I took some video clips inside my house (-40 below windchill outside) to compare how the Plus matches up to my $30 LightDow “fake” 4K/24fps. It’s digital zoom maxes out at 4X. I zoomed the Plus to estimated 4X and recorded at 4K/30fps. I took screen grabs off of both inside videos. Frig is about 12 feet from camera.
    LightDow 4X digital zoom screen grab [​IMG]

    SJ8 Plus 4X digital zoom screen grab [​IMG][/URL][/IMG]
     
  8. karjak

    karjak New Member

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  9. Sulev Svilponis

    Sulev Svilponis Elite

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    Your fridge shots are incomparable, they have too different exposure. I suspect, that the SJ8plus cranked the ISO value up, hence the ISO noise. Those cameras with a tiny sensor are not meant for shooting in the dark.
    I like the nuthatch (the scope image)!
     
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  10. karjak

    karjak New Member

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    Thanks Sulev. It is a bummer I cant' get outside to do a valid test as wind chill near 40 below. I think my screen grabs from videos through LightDow might be as good as what I would get from a still frame picture from it. Here is a link to a Composite video of some recorded clips through the scope.

    More important I got some good info on DashCamTalk forum from "Drekitech" who did a comparison review on the zoom of the Plus and Pro. Here is the Link https://drive.google.com/drive/folders/1WVf2_sTk3jWwd1GH7QWLHOQn6088x-RR

    If you are interested he has some other helpful comments directed to me. Here is the link to the forum discussion:https://dashcamtalk.com/forum/conversations/what-is-video-output-for-lightdow-4k-ultrahd.11803/
     
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  11. Michael Dittrich

    Michael Dittrich Member

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    Here some footage in 1080p H.265 (HEVC) using the flat color profile:
    https://drive.google.com/drive/folders/1gUSsNnVoogYAuaTproA3DRQD2RLRzjb1

    As there is unfortunately no scale of the zoom given, I have
    - No zoom
    - Some zoom
    - 8x

    A Smart Zoom is really missing using the portion of the 12MP sensor required to achieve 1080p (2MP) without any scaling.

    In my opinion the 8x is completely unusable an makes no sense and is a dirty marketing joke.
    Zooming in a little bit is OK, but mostly limited due to the way too low bitrate in 1080p.

    Don't view it on a smartphone as downscaled to a tiny display nearly everything looks good;)
     
    Last edited: Mar 14, 2019
  12. Sulev Svilponis

    Sulev Svilponis Elite

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    Actually I was surprised, how good the 8x zoom is. I expected lot worse. And it is really 8x zoom, I did some measuring and checked out, that it is exactly 8x zoom.
    Your "Some zoom" is a bit more than 2.4x zoom, according to my measurements.
     

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