Video recording more zoomed in that image capture

Discussion in 'iPhone' started by Markyboy81, Apr 14, 2012.

  1. Markyboy81 macrumors 6502a

    Joined:
    Oct 30, 2011
    #1
    Apologies if this had been covered, wasn't able to do a search on tapatalk.
    Was trying to record a video the other day and found it was a lot more zoomed in than in image capture mode.
    Is there any reason for this and any way to change it? I'm sure this wasn't the case with my old N8
     
  2. stevemiller macrumors 65816

    Joined:
    Oct 27, 2008
    #2
    i believe its caused by image stabilization. would be nice if we had the option to turn it off - sometimes the wider FOV is of greater value than the digital stabilization. since its just sliding the already recorded image around, the stabilization can't correct motion blur or rolling shutter. In fact it just draws more attention to these things: the image stays put, but blurs and distorts without any obvious reason to the viewer.

    at the end of the day its a cellphone camera aimed at casual users, and apple seems to have decided by having the feature always on, it will hopefully elevate bad handheld camerawork to "ok" at the expense of limiting the maximum potential of the sensor.
     
  3. Small White Car, Apr 14, 2012
    Last edited: Apr 14, 2012

    Small White Car macrumors G4

    Small White Car

    Joined:
    Aug 29, 2006
    Location:
    Washington DC
    #3
    Nope, all video-shooting iPhones have done this whether or not they have image stabilization.

    Mostly, it's because the aspect ratio of the sensor doesn't match 16x9, so you're going to lose some image right there as they have to crop it to cut a rectangle out of the picture.

    Also, I suspect that they can't use absolutely all of the pixels. 1920x1080 is far less than the total sensor size, so something has to be done. Taking the whole whole image and shrinking it down would probably lead to weird math like "put these 3 pixels in these 2 spots". Doing things in even numbers leads to better pictures.

    The video is 58.8% the width of the sensor. That's some wacky math and I suspect they cropped the starting number down to something that makes the equation easier.

    So they may not be using 100% of the sensor's pixels to start with.
     
  4. stevemiller macrumors 65816

    Joined:
    Oct 27, 2008
    #4
    ahh, good point!
     
  5. Moonjumper macrumors 68000

    Joined:
    Jun 20, 2009
    Location:
    Lincoln, UK
    #5
    If you try image stabilisation in iMovies, it crops the image a lot and zooms what remains. So I thought the same might be true of iPhone recording, but Small White Car's reply makes a lot of sense. Sounds like a block of 4 sensor points makes one pixel in the video. Although I also assume the extra pixels to the side are used in image stabilisation as there is room to move the captured area around the sensor.
     
  6. Markyboy81 thread starter macrumors 6502a

    Joined:
    Oct 30, 2011
  7. terraphantm macrumors 68040

    Joined:
    Jun 27, 2009
    Location:
    Pennsylvania
    #7
    It takes less processing power to use exactly 1920x1080 pixels than it does to use the whole sensor (cropped to 16:9) and scale it down. The downside of this is that there's a cropping factor relative to the native fov
     

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