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Question about video....

Discussion in 'Filmmaking' started by Djarum, Aug 26, 2010.

  1. Djarum

    Djarum Super Moderator

    Dec 15, 2009
    Huntsville, AL, USA
    Jason
    How exactly does the E-P1 take video? Exactly what I mean, is that it will do 720p, but the field of view is the same as taking a picture. So, this tells me the camera is not croping down to take video. What is it exactly doing then? Is it pixel binning or is it just selecting specific rows and columns of pixels to use across the entire frame to take the video?
     
  2. everythingsablur

    everythingsablur Mu-43 Veteran

    412
    Aug 4, 2010
    Toronto, ON
    Well, a 4/3 sensor is 12 mp effective, so native resolution is 4000x3000. 720p video is 1280x720 in terms of hard resolution. Taking into account the change in aspect ratio (4:3 to 16:9), the sensor in 16:9 would be working with a resolution of 4000x2250 (I'm guessing, don't have a camera on hand).

    At that point it's anyone's guess really since I doubt an Oly/Panny engineer is in the house. The simplest solution would be cropping just the specific resolution video needs, but that would change the FOV slightly. My guess would be binning.
     
  3. JohnF

    JohnF Mu-43 Regular

    183
    Apr 1, 2010
    Oberursel, Germany
    Hi -

    The field of view changes only slightly: 720P is, after all, a 16:9 format, rather than a 4:3 format. When you film, the upper and lower parts of the frame are blacked out.

    I'm not an engineer either, but basically it's a software thing. When you take a still photo, values from the sensor are read in a large dump to a file in memory and is then converted into RAW or JPG format according to how you camera is set up. When you tell the camera to record video, values from the sensor are streamed continuously via filtering (i.e. not as a raw file) to your memory device of choice. In order to speed things up, values are cross-referenced and combined (aka binning) for the appropriate format.

    Theoretically (and in reality, as we've seen with the Panasonic hacks) the 720p limit on the EP1 is arbitrary and with alternative software (and hardware!) you could generate video as detailed as the sensor. Heat problems, data bottlenecks and the like prevent this, though.

    JohnF