Are anybody else's video's automatically zoomed in a little? (iPhone 4)

Discussion in 'iPhone' started by mrat93, Jun 24, 2010.

  1. mrat93 macrumors 65816

    mrat93

    Joined:
    Dec 30, 2006
    #1
    Something I noticed... When I switch from photos to videos on the back camera, it automatically zooms in a little bit with videos. Anybody else getting this problem? It wasn't like this on my 3GS.
     

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  2. MacGeekDC macrumors 6502

    Joined:
    Mar 6, 2008
    Location:
    Northern Virginia
    #2
    Same thing on mine.
     
  3. ds111 macrumors member

    Joined:
    Dec 27, 2009
    #3
    Same here. I wonder if this is actually an issue?
     
  4. VSMacOne macrumors 601

    VSMacOne

    Joined:
    Oct 18, 2008
    #4
    Same here. All I can make of it is that it has something to do with the 720p video recording... But I don't have a technical explanation for it.
     
  5. Matthew Yohe macrumors 68020

    Joined:
    Oct 12, 2006
    #6
    Yeah, because it takes photos at 2592x1936 and video at 1280x720.

    This is by design.
     
  6. coasterswim macrumors 6502

    Joined:
    Dec 4, 2008
    #7
    This explains nothing.
     
  7. Matthew Yohe macrumors 68020

    Joined:
    Oct 12, 2006
    #8
    Maybe if you turned on your brain and thought about it for awhile, you might realize it explains everything.

    Example:

    Draw a 10x10in square. (This is the picture mode resolution)

    Now draw in a little happy scene inside the box. Maybe a hill, a house, some flowers. Oh, don't forget the sun!

    Now, draw another box inside that box. Make it 5x5in square. (This is the movie mode resolution)

    No matter what you do, you can't put that entire scene inside that little box!

    Voila!
     
  8. mrat93 thread starter macrumors 65816

    mrat93

    Joined:
    Dec 30, 2006
    #9
    I understand what you're saying, but then why does the 3GS not have this issue? The dimensions of pictures and videos are completely different there.
     
  9. PureRED macrumors member

    PureRED

    Joined:
    Jun 18, 2009
    Location:
    San Marcos, Texas
    #10
    ...Because the 3G/S didn't record in 720p. That's why it zooms in. It's not an 'issue' and there's nothing you can do about it.
     
  10. Matthew Yohe macrumors 68020

    Joined:
    Oct 12, 2006
    #11
    Oh, I figured you knew you could "zoom out." They do this to "fill" the viewing screen but you can still double tap and zoom out.
     
  11. admanimal macrumors 68040

    Joined:
    Apr 22, 2005
    #12
    It probably has something to do with the image capture process itself and/or how the sensor adapts to capturing different resolutions. You'll notice that the front camera on the iPhone 4 behaves the same way as the 3GS camera.

    The HD camera on the iPhone 4 appears to just shut off pixels on the sensor around the outside of the video that would normally appear in a still photo. This has the effect of narrowing the field of view of the video camera, which gives the appearance that the image has been zoomed in compared to a still photo. Of course in reality the picture is still being scaled down to fit in the iPhone's display.

    The 3GS camera and front iPhone 4 camera do something different. I don't know what exactly, but one possibility is that the sensor is actually capturing full resolution images (and therefore getting the same view as the still camera), but they might be lower quality readings to allow it to capture at frame rate and then the images are scaled down to VGA....or it might be something else. The moral of the story is that there is something different happening during the capture process.
     
  12. mrat93 thread starter macrumors 65816

    mrat93

    Joined:
    Dec 30, 2006
    #13
    It still doesn't show the same area as in picture mode.
     
  13. CashDude macrumors regular

    Joined:
    Jun 21, 2010
    #14
    It records in 720p but the screen is not 720p.

    It's like when you divide a fraction and have a remainder. Remember widescreen movies on 4:3 TVs? There were huge black bars on top and bottom so you could see the whole picture without being zoomed in.

    It's the same thing here, but there are only small black bars because the ratio is pretty close. You can zoom in to eliminate the black bars, but you lose some of the image on the left and right sides.
     
  14. mrat93 thread starter macrumors 65816

    mrat93

    Joined:
    Dec 30, 2006
    #15
    So basically, what you're saying is that the dimensions of the videos taken in 720p and pictures taken with the 5mp camera are not proportional, whereas on the 3GS pictures' and videos' dimensions are proportional?

    Sorry, I have absolutely no knowledge on how camera technology works.
     
  15. Matthew Yohe macrumors 68020

    Joined:
    Oct 12, 2006
    #16
    Yup.

    [​IMG]

    The reason for the zoom difference is because Apple wants to maintain the 720p mode which basically "restricts" the sensor to only display a width that maintains the 16:9 ratio (1.777777).

    They COULD maintain the ratio with the still photos, but then you would just be wasting ~500 pixels on the sensor. (2592*.5625 = 1458)
     

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