Mega pixel and print size and digital camera

Discussion in 'Digital Cameras' started by Jamie, Oct 16, 2004.

  1. Jamie

    Jamie Guest

    Hi There

    Was wondering if anyone can give me any information regarding
    Mega Pixels and print size.

    what would be a good MP for 5 x 7 prints or something abit larger.
    also optical zoom in the camera is important. 4 x and upwards
    the more manual features the better.
    DSLR is not an option.

    Does anyone have any Digital camera recommendations.

    Thanks in advance..

    Jamie, Oct 16, 2004
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  2. Any number of pixels over 2 will do that. I like my Oly E-10...its not a new
    camera any more and one like it might be had for a good price.
    Gene Palmiter, Oct 16, 2004
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  3. Jamie

    GT40 Guest

    Anything above 2MP for a 5x7
    GT40, Oct 16, 2004
  4. You are getting some nonsense answers. just divide the pixel width
    and lenght by 300 and you get the size print in inches that will yield
    a print without loss of detail. Some say you can divide by 250 or
    even 200, but many people will note quality changes using that

    My Nikon 4300 manual gives the following recommendations for picture
    sizes based on setting the camera for different pixel sizes. 2272
    (4meg) is 7.5 x 5.5 in, 1600 (about 3 meg) is 5.5 x 4 in, and 1280
    (about 2.1 meg) is 4.5 x 3 in. In actual practice a 4 meg will yield
    a fairly good 8 x10 if well focused and exposed. a 3 meg camera will
    give about a 5 x7 and a 2.1 meg will give a 3 x 5).

    Check the nikons, my 4300 is 4 meg with lots of manual features. the
    4100 and 4200 I belive have fewer manual features, but do not believe
    what clerks tell you are what reviews select to report on. You really
    need to look at the manual to see what the features the camera has.
    You might also want to check the Kodaks which have a much larger LCD
    George E. Cawthon, Oct 18, 2004
  5. Jamie

    David Azose Guest

    Here's another way to look at it:
    A general rule of thumb is that the largest file size you can get from a
    point and shoot digital camera is approximately 3 times the number of
    megapixels. So a 3 megapixel camera should yield about a 9MB file and a
    4 megapixel camera a 12MB file. This assumes the hightest resolution and
    least amount of compression for your camera.

    Then open PhotoShop, go to FILE>NEW. You are presented with a dialogue
    box where you can enter the WIDTH (in inches), the HEIGHT (in inches)
    and the resolution (in pixels per inches). Once you fill in this
    information, you are presented with the file size required near the top
    of the dialogue box. This procedure works to tell you what file size is
    requires for any print size at any resolution. For example, if one fills
    in 8 inches for the WIDTH and 10 inches for the HEIGHT and 300 ppi for
    the resolution, you can see that 20MB is required. This file size may be
    necessary if outputting to a photographic device that prints on real
    photographic paper (not an inkjet printer). You could probably get away
    with a 10mb file and still get an acceptable 8x10 print from a good
    photo quality inkjet printer.

    David A.
    David Azose, Oct 18, 2004
  6. Jamie

    Prometheus Guest

    Rather like the smeg SD9/10 which detects light at 3.2 million loci and
    the makes up another 9.8million with its companion software.
    Prometheus, Oct 18, 2004
  7. Jamie

    Crownfield Guest

    shows how upsizing without real pixels is empty.
    at 25 ppi !!

    I do photo wraps from digital images at 72 ppi,
    and would never go that low.

    but then I never had to do it from a 3mp sigma.
    Crownfield, Oct 19, 2004
  8. Jamie

    Prometheus Guest

    The sensor in the SD10 has 2268 columns x 1512 rows (as stated at, or from it has a pixel pitch of 9.12æm
    centre-to-centre spacing of pixel locations with an effective area of
    20.7 mm x 13.8 mm; both of which give a total of 3.43 million pixels in
    the image plain. The sensor only detects light normal to its surface at
    the intersections of the rows and columns, it has no information about
    the light falling on the interstice. The SD10 gets 3.43 million pixels
    from 10.3 million sensor elements in 3.43 million locations on its
    sensor. The 10D gets 6.3 million pixels from 6.3 million (3072 columns x
    2048 rows) distinct locations in the image plain. Neither interpolates
    pixels, by default. They both interpolate colour, although the Foveon
    attempts to measure full colour at each pixel. See Bayer.htm for an explanation of the
    Bayer process and there is a Bayer algorithm
    http://www.tortuga.comau/products/info/cfa2bmp.html from these you will
    see that the luminosity at each detector is used and guessed, unlike the
    SD10 which has to guess.

    A Bayer sensor outputs the exact (as least as any measurement can)
    luminance for green on a green sensor, the same goes for blue and red.
    The other two luminances are computed from the 8 surrounding pixels.
    This computation assumes that the chrominance varies slowly. This
    assumption can be made because our own seeing mechanism is not all that
    good at detecting chrominance changes, i.e. if there is a "mistake" in
    the actual luminance then we will not see it.

    The Foveon sensor also measures an approximation to reality, since its
    colour response is so far from matching the human perception of colour.
    The colour you see in any Foveon image is at least as much a
    "computer-generated artefact" as a Bayer image. In addition, the low
    spatial resolution of the Foveon sensor irreparably loses spatial
    information that would have been captured by a Bayer sensor, aliasing it
    to false detail because there's no anti-aliasing filter.

    SPP allows you to manipulate the data whilst it was still in the camera
    but as such they are not straight from the sensor, in fact since you
    stated that they are straight out of SPP we must conclude that you used
    SPP to multiply the number of columns and rows thereby inventing values
    where there are no detectors. The result of this manipulation tells us
    nothing about the number of pixels the SD9 has. Sigma do tell us it has
    2268 columns x 1512 rows (as stated at, any image having
    more has been manipulated by external software.

    Let me try to simplify it; SPP might "optionally output 14MP images" but
    the sensor only resolves 3421656 unique points in the image plain,
    anything more than this is a software cheat by the user! Or even
    simpler: more than 3421656 is dishonest, less other than a crop is a
    disservice. Simpler still - you dissemble.

    Your 14MP SD9 uses luminance and chroma extrapolation to provide 10
    million pseudo pixels where it can not detect light, the 10D uses chroma
    interpolation to provide colour at the 6.3 million where it does detect
    the luminance; not even remotely the same thing.
    Prometheus, Oct 19, 2004
  9. Jamie

    Big Bill Guest

    It might be if they had 10.3 MPs.
    In reality, they have a native output of 3.4 MPs; the higher MP images
    I thought you didn't do interpolation?

    Bill Funk
    Change "g" to "a"
    Big Bill, Oct 19, 2004
  10. Jamie

    Prometheus Guest

    Since there are more guessed than real shouldn't that be extrapolated.
    Prometheus, Oct 19, 2004
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