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Old Apr 21, 2004, 12:11 PM   #1
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Default ZOOM CAPABILITY and Image quality questions! HELP!

Can someone please help me understand why there are no digital cameras that have an 8 MP sensor with more than a 7X zoom? There are 4 MP cameras with a 12X optical zoom. Why is it that zoom capability decreases as megapixels increase? I want an 8 MP camera with at least a 10X optical zoom but it does not exist!
Can anybody tell me why?
Also, it seems that the sample photos of the Canon Pro1 8MP camera are not all that much beter with detail than my Canon Pro90IS which is a 2.6 MP camera. There is somewhat more detail but certainly not 3X the detail!!
Can someone help me to understand this?
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Old Apr 21, 2004, 12:38 PM   #2
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The new Sony Sensor used in the current crop of 8 megapixel "prosumer" cameras is 2/3".

The lower resolution sensors used in the current crop of "superzoom" models are smaller.

By using a smaller sensor, the manufacturers can use a much smaller lens to get more "35mm equivalent" focal length.

Bear in mind that most of the Super Zoom Models are using sensor sizes of either 1/2.7" (.37") or 1/2.5" (.40"). The newer "prosomer" 8 megapixel models sensors using a larger 2/3" sensor.

So, they will require a much larger lens for the same focal length.

Given current technology, the noise levels would simply be too high to try and get 8 megapixels in a smaller than 2/3" sensor. In fact, many people feel that this sensor is far too small already to effectively work with 8 Megapixels of resolution (noise, purple fringing, etc.).

This is the main reason that the Digital SLR's have much lower noise (larger photosites for each pixel, using dramatically larger sensors). Of course, the larger sensors also require larger lenses to get the same focal length equivalency.

As far as detail, remember that resolution is computed by multiplying width x height. So (all else being equal), it takes 4 times the resolution to double the image size (and detail captured).
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