I just bought my first digital camera, a Minolta Dimage EX1500 Zoom. I shopped very carefully, and found numerous websites with cross-camera comparisons of all the stats and image quality and whatnot.

HOWEVER: every picture I saw was taken at the high-resolution mode of each camera. I was thus very shocked when I finally downloaded my initial pictures (taken at the camera's 1/4-size image mode of 640x480), and I had really bad jaggies and overpronounced pixellation even in the highest-quality mode.

The native resolution of the camera is 1344x1008. When I take the same photo at that res, I don't get the problems.

It seems that rather than using 640x480 worth of CCD pixels for the low-res mode, the camera is internally scaling a full-size image down to that resolution, a 47% reduction. This is what's causing the jaggies. If this is indeed what's going on (and everything I can understand seems to indicate this is), then my hats off to the engineers for an awesomely idiotic decision to give a 47% scaling factor for the low-res... at the very least, a 50% factor would allow for much better results, I would think.

My question is: do most/all digital cameras accomplish lower resolutions in this manner? Or do they actually refocus/rezoom the lens to only use the inner CCD pixels?

The camera takes great pictures in full-res mode, but the 1/4-res-mode pictures are unusable, because the jagginess is so pronounced at any color boundaries. Is this a dumb Minolta thing, or is this true in many/most cameras?

-- Michael Weiss-Malik (notyou@asu.edu), December 03, 1999