Question About Resolution

Discussion in 'Digital Photography' started by Crash, Aug 28, 2003.

  1. Crash

    Crash Guest

    My camera's maximum resolution is about 1.4 megapixels (Olympus E100rs), but
    I usuallly shoot at a lower resolution in order to get more pictures in
    continuous mode. Specifically, I usually shoot at 1024 x 768, which is
    about 0.8 megapixels.

    My question is this. When I set the camera to 1024 x 768 and take a
    picture, are all 1.4 active, megapixels on the focal plane being used to
    record the image? If so, the camera has to be 'scaling' that image down to
    0.8 megapixels before sending it to the compact flash card. Or, is the
    camera actually only using a 1024 x 678 pixel subset of the focal plane to
    record the image? That way no scaling of the image would be required before
    sending the image to the CF card?

    It seems to me that if the camera is scaling the image down from 1.4 to 0.8
    mpixels, I would get a higher quality image than if a 1024 x 768 subset of
    the focal plane was used. This is because the scaled image would, in
    effect, be anti-aliased compared to the unscaled image. Also, if no scaling
    is used, the camera optics would somehow have to be changed to bring the
    image into focus on a smaller region of the focal plane.

    My guess is that my camera, in fact, all digital cameras do some realtime
    scaling down of images when they are set to less than their maximum
    resolutions. Anyone know what the deal is with this? Thanks.
     
    Crash, Aug 28, 2003
    #1
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  2. Crash

    Ken Alverson Guest

    "Crash" <> wrote in message
    news:nXd3b.279861$uu5.62518@sccrnsc04...
    >
    > My question is this. When I set the camera to 1024 x 768 and take a
    > picture, are all 1.4 active, megapixels on the focal plane being used to
    > record the image? If so, the camera has to be 'scaling' that image down to
    > 0.8 megapixels before sending it to the compact flash card.


    Yes, the camera is performing the same operation as digital zoom, only with a
    multiplier less than 1.0. In theory, you are right when you say that this
    should generate a higher quality image than a straight 1024x768 shot, due to
    the downsampling, however scaling algorithms vary wildly from camera to
    camera, so this may not be the case.

    I haven't done any comparisons of in-camera downsampling, but on the previous
    few cameras I've owned, in-camera upsampling (digital zoom) was atrocious.
    More recent cameras probably do a better job, but I wouldn't know - my current
    camera doesn't do digital zoom.

    Ken
     
    Ken Alverson, Aug 28, 2003
    #2
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  3. Crash

    Don Stauffer Guest

    The camera uses all the pixels, but does a downsampling or averaging
    algorithm before storing image in memory.

    Crash wrote:
    >
    > My camera's maximum resolution is about 1.4 megapixels (Olympus E100rs), but
    > I usuallly shoot at a lower resolution in order to get more pictures in
    > continuous mode. Specifically, I usually shoot at 1024 x 768, which is
    > about 0.8 megapixels.
    >
    > My question is this. When I set the camera to 1024 x 768 and take a
    > picture, are all 1.4 active, megapixels on the focal plane being used to
    > record the image? If so, the camera has to be 'scaling' that image down to
    > 0.8 megapixels before sending it to the compact flash card. Or, is the
    > camera actually only using a 1024 x 678 pixel subset of the focal plane to
    > record the image? That way no scaling of the image would be required before
    > sending the image to the CF card?
    >
    > It seems to me that if the camera is scaling the image down from 1.4 to 0.8
    > mpixels, I would get a higher quality image than if a 1024 x 768 subset of
    > the focal plane was used. This is because the scaled image would, in
    > effect, be anti-aliased compared to the unscaled image. Also, if no scaling
    > is used, the camera optics would somehow have to be changed to bring the
    > image into focus on a smaller region of the focal plane.
    >
    > My guess is that my camera, in fact, all digital cameras do some realtime
    > scaling down of images when they are set to less than their maximum
    > resolutions. Anyone know what the deal is with this? Thanks.


    --
    Don Stauffer in Minnesota

    webpage- http://www.usfamily.net/web/stauffer
     
    Don Stauffer, Aug 28, 2003
    #3
  4. Crash

    jriegle Guest

    I don't know about this specific camera, but most will downsample the image.

    To verify, take two pictures of the same subject at the same distance, one
    at each resolution. If the .8mp setting looks zoomed in, it is using a
    smaller area of pixels, If it looks the same, aside from the lower
    resolution, it downsampling.

    My Olympus D360-L had a digital zoom mode at 640x480 where it used the
    central area of the pixels to make it looked zoomed in. However, in lower
    res mode without the digizoom it downsampled the image.

    John

    "Crash" <> wrote in message
    news:nXd3b.279861$uu5.62518@sccrnsc04...
    > My camera's maximum resolution is about 1.4 megapixels (Olympus E100rs),

    but
    > I usuallly shoot at a lower resolution in order to get more pictures in
    > continuous mode. Specifically, I usually shoot at 1024 x 768, which is
    > about 0.8 megapixels.
    >
    > My question is this. When I set the camera to 1024 x 768 and take a
    > picture, are all 1.4 active, megapixels on the focal plane being used to
    > record the image? If so, the camera has to be 'scaling' that image down

    to
    > 0.8 megapixels before sending it to the compact flash card. Or, is the
    > camera actually only using a 1024 x 678 pixel subset of the focal plane to
    > record the image? That way no scaling of the image would be required

    before
    > sending the image to the CF card?
    >
    > It seems to me that if the camera is scaling the image down from 1.4 to

    0.8
    > mpixels, I would get a higher quality image than if a 1024 x 768 subset of
    > the focal plane was used. This is because the scaled image would, in
    > effect, be anti-aliased compared to the unscaled image. Also, if no

    scaling
    > is used, the camera optics would somehow have to be changed to bring the
    > image into focus on a smaller region of the focal plane.
    >
    > My guess is that my camera, in fact, all digital cameras do some realtime
    > scaling down of images when they are set to less than their maximum
    > resolutions. Anyone know what the deal is with this? Thanks.
    >
    >
     
    jriegle, Aug 29, 2003
    #4
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