Chopping a 3 Megapixel chunk out of an 8 Megapixel photo

Discussion in 'UK Photography' started by Alan Clifford, Aug 8, 2005.

  1. I am looking at a buying a new camera that has more pixels but a shorter
    zoom. The original camera, Olympyus 730, can do 2048 x 1536 at 380 mm

    The new camera, Konica Minilta A200, can do 3264 x 2488 at 200 mm. If I
    chop a 2088 x 1536 chunk out of this, what would be the equivent xxx mm?

    --
    Alan

    ( If replying by mail, please note that all "sardines" are canned.
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    Alan Clifford, Aug 8, 2005
    #1
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  2. Alan Clifford

    Trev Guest

    No Smaller area yes but not the same compression of perspective. It the
    same as using the digital zoom fills the frame as a longer lens would but
    has the perspective still of the 200m focal length. But dont forget the
    Minolta tele converter ACT 100 If you need it.

    Though it might suit the effect you want . At least you have enough pixels
    left for a good print after you have cropped a Lot of space out of the
    image. But the good point is the 28mm wide angle, that you cant cheat.
     
    Trev, Aug 8, 2005
    #2
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  3. 312mm

    Not quite as long. The actual effect will be comparable. 'Perspective'
    is irrelevant at these distances as it is a factor of lens to film plane
    distance/lens to subject distance(s), and these cameras are so tiny and
    the lenses so long that they equal optical perspective without
    photographic optics coming into it.

    David
     
    David Kilpatrick, Aug 8, 2005
    #3
  4. On Mon, 8 Aug 2005, David Kilpatrick wrote:

    DK> > I am looking at a buying a new camera that has more pixels but a shorter
    DK> > zoom. The original camera, Olympyus 730, can do 2048 x 1536 at 380 mm
    DK> >
    DK> > The new camera, Konica Minilta A200, can do 3264 x 2488 at 200 mm. If I
    DK> > chop a 2088 x 1536 chunk out of this, what would be the equivent xxx mm?
    DK>
    DK> 312mm
    DK>
    DK> Not quite as long. The actual effect will be comparable.

    The reason behind this thought is depth of field at the shorter end.
    Whilst not losing the telephoto at 3 Megapixel, the camera has a larger
    ccd. This means that the lens will be physically larger so that the
    perfect depth of field from in front of my nose to infinity, inherent with
    the small lenses, mught be reducted a tad.

    --
    Alan

    ( If replying by mail, please note that all "sardines" are canned.
    There is also a password autoresponder but, unless this a very
    old message, a "tuna" will swim right through. )
     
    Alan Clifford, Aug 8, 2005
    #4

  5. There are some other quite complex factors at work with the A200/A2
    lens. It is, in effect, a longer zoom with a negative converter group at
    the very rear linking it to the CCD. This enables the lens to have a
    reasonable range of 'real' apertures down to f9.5 at 7.2mm focal length
    without using waterhouse stops - it has a true variable aperture, but
    it's not positioned traditionally.

    As a result, the actual pictures from the '28-200mm' zoom have rather
    less depth of field than might be possible - you can get pretty good
    differential focus effects even at 7.2mm.

    The same goes for a few similar digital camera designs. They would look
    very odd indeed if scaled up to 35mm size (the A200 lens would, if made
    to cover 35mm, have a 192mm front filter thread!)

    David
     
    David Kilpatrick, Aug 8, 2005
    #5
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