I NEED a formula!!!

Discussion in 'Digital SLR' started by RichA, Apr 20, 2005.

  1. RichA

    RichA Guest

    I was told that unless your lens resolves 360 lines per mm, you can't
    support the full resolution provided by 8 megapixels.
    Is there a formula for this anywhere?
    RichA, Apr 20, 2005
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  2. That sounds rather arbitrary. Basically, for the camera you are
    considering, take the number of pixels horizontally, divide it by the
    sensor width in mm to get the pixels per mm. Half the pixels per mm to
    get the cycles per mm. [Lines per mm might mean lines or line pairs - the
    term is ambiguous.] At that spatial frequency, the system response must
    be zero to avoid aliasing. What is this limiting spatial frequency for
    your system?

    Where you go from there is subjective as to what MTF you need from the
    lens at what spatial frequency, and it's outside my direct scope of
    experience. As a starter, perhaps a 30% to 50% MTF at half the limiting
    spatial frequency? The 360 lines per mm may be a limiting resolution,
    i.e. something like a 1% or 2% MTF.

    David J Taylor, Apr 20, 2005
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