Original Mobius night recording with 4mm ~ F1.2 lens (!)

Discussion in 'Mobius' started by dirkzelf, Oct 14, 2017.

  1. jokiin

    jokiin Well-Known Member Manufacturer

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    regardless I would still always suggest only buying from a reseller they have listed as authorised, not worth the hassle of dealing with any non approved seller if any problems
     
  2. dirkzelf

    dirkzelf Well-Known Member

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  3. dirkzelf

    dirkzelf Well-Known Member

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    while going through some footage I cam along this "phenomenon":

    vlcsnap-2017-11-11-02h41m56s213.png vlcsnap-2017-11-11-02h41m05s240.png

    Anyone even noticed that?!?
     
  4. TonyM

    TonyM Well-Known Member

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    That looks like your windscreen wiper pushing some water across the screen
     
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  5. dirkzelf

    dirkzelf Well-Known Member

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    I have no idea why, but when the wiper crosses the letters on the building, all of a sudden, they seem a lot sharper ....?!?!?
     
  6. Dashmellow

    Dashmellow Well-Known Member

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    I'm "guessing" that for a very brief moment your wiper blade is mimicking the effect of a focal plane shutter at it passes over the brightly illuminated sign on the building as well as the reflection in the road. It's as if the camera is shooting at a faster shutter speed for that one moment and only in those isolated spots. The image is also briefly darker at those locations. The phenomenon would be a combined effect of the camera's electronic rolling shutter and the wiper blade "shutter". I'm not 100% certain that this is the explanation but this is my theory at this point.

    The wiper blade also seems to be pushing water across the glass which is refracting the light but that seems to be a separate phenomenon.

    A focal plane shutter is a mechanical set of "curtains" that very quickly shoots across the film plane in a camera.

    focal_plane.jpg

    FPS_diagram_2.gif
    Dotted line is the sensor. Colored rectangles are the shutter blades.


    Notice that the road surface also appears sharper right at the point where the wiper blade "shutter" is passing.
    Compare it to the first screen shot above where the wiper blade is in a different location and the road in the same spot is not as detailed and is blurred.

    roadsurface2.jpg

    roadsurface1.jpg
     
    Last edited: Nov 11, 2017
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  7. harsh

    harsh Well-Known Member

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    Looking for a 2.3mm or less with f/1.2-1.4, anyone's ever looked or come across one?
     
  8. dirkzelf

    dirkzelf Well-Known Member

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    shortest I've seen is 2,8mm...

    Oh, here's the same route from the 119s' perspective (longer version):

     
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  9. Dashmellow

    Dashmellow Well-Known Member

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  10. TonyM

    TonyM Well-Known Member

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    I was thinking the same thing, but could not have presented it as well as you. Thanks for explaining.
     
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  11. Gabacho

    Gabacho Well-Known Member

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    Informative explanation
     
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  12. Nigel

    Nigel Well-Known Member

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    Normally the image data is updated with changes since the last frame to reduce the bitrate required. With a limited bitrate, over a number of frames parts of the image that only have small changes to brightness or colour or position become increasingly out of date and inaccurate, when the black wiper blade wipes away all the old image data with complete blackness it then gets replaced by a fresh, completely up to date and accurate image which then starts to deteriorate again as it only receives updates over the following frames.
     
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  13. dirkzelf

    dirkzelf Well-Known Member

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    I've made some in-cabin recordings, with the camera's stuck to the back window (vertical) of the truck's cabin, looking through the cabin and the front windshield, one disadvantage, you can actually see the ugly guy that drives it..... :eek:

    Note how I use the phone on the dashboard to record speed in the video..... :whistle:



    watch in 1440p for best results...:



    watch in 1440p for best results...:







    Needs to be said, the F1.4 / 2.8mm is great for this purpose....

    I've also tried the F1.2 / 4mm, but it's way to narrow, besides it was oof, so needed to refocus.

    Hope you like it.
     
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  14. dirkzelf

    dirkzelf Well-Known Member

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    Has anyone noticed something specific about the cabin recordings?
     
  15. M Basta

    M Basta Active Member

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    To you experts - I’m looking at you @Dashmellow, @dirkzelf and @TonyM:

    First, thanks so much for these great threads. It has opened mine and I’m sure countless others’ eyes on the possibilities with the Mobius. I’m wowed with these results and am even wondering why bother with “newer” cams these days (I mean that seriously).

    Second, as I’m a total noob on this, I’d appreciate your input on a couple of lenses I’m considering (fitment, appropriateness for the Mobius, etc). The links you guys have provided would be the easiest routes, but I prefer to order from Amazon (for speed of delivery/convenience/confidence mostly) and I think these are the closest matches from your three threads (I could not find your exact ones on Amazon, unfortunately).

    https://www.amazon.com/gp/B00REFRRKK

    https://www.amazon.com/gp/B071FL9D3C

    My ~4 year old Mobius has the A lens and my goal is to replace it with better quality at night primarily, and a little more zoom (I’d think anywhere from 2.8 to 10mm would be ideal).

    Thanks

    Edit: fixed incorrect link
     
    Last edited: Nov 14, 2017 at 3:45 PM
  16. dirkzelf

    dirkzelf Well-Known Member

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  17. M Basta

    M Basta Active Member

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    Thanks for pointing that out. Don’t know why I’d assumed that was an f1.2. I was sure I’d read that somewhere on the site but it’s definitely not mentioned.

    Also, I meant to link the JETSECAM as the second cam (now fixed in my original post) but hadn’t realized it was the same as yours in the op. The varifocal lens I’m already buying as it’s identical to the one @Dashmellow had recommended in his thread. I was basically trying to figure which of the two fixed lenses to get. Thanks for solving that for me!
     
  18. Lola

    Lola Well-Known Member

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    @dirkzelf Do you have any more footage of the f1.2 Mobius during the day?
     
  19. dirkzelf

    dirkzelf Well-Known Member

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    Yes, but I'm not posting them all, why do you ask?
     
  20. dirkzelf

    dirkzelf Well-Known Member

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    How about the cabin recordings? Have you seen something that's remarkable? I did, but I'm really curious if we all see it....
     
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