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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" <> 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

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

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.
>
>