Incredibly Small Active CCD Sizes

[J. Stephen McDonald]

When the cameras that have the "Smart Zoom" or "Extended Optical Zoom" feature, shrink their active CCD sectors to produce images with lower pixel-sizes, they get really small. For a camera with 7 Megapixels and a .4-inch CCD size, I made some calculations to determine how much active area is being used for the various resolutions:

7 MP: .4-inch diagonal measure CCD sector, with a .077 sq.in. area
5 MP: .353-inch CCD sector, with a .06 sq. in. area
3 MP: .285-inch CCD sector, with a .036 sq. in. area
2 MP: .226-inch CCD sector, with a .024 sq. in. area
640 X 480 (VGA): .089-inch CCD sector, with a .0068 sq. in. area

The figures for the CCD sector sizes are calculated to allow for the approximately 10% extra pixels that are inactive. The 640 X 480 sector's diagonal measure is only about 1/12th-inch. The CCD of my first 640 X 480 camcorder, has a sensing area about 71 times greater than this.

The Smart Zoom, in its various forms by different manufacturers, can be turned off, so you don't have to deal with the ridiculously-high 57X zoom in 640 X 480, if you don't want it. It'll be interesting to see what kind of quality you might get when shooting with such a tiny CCD sector. Also, this feature shifts gradually off, as you zoom back into the wide end, so you get the full wide angle of view.