Why don CMOS APS sensors have CCD like performance?
Typical APS Sensors have many fundamental drawbacks. Each pixel in an APS sensor includes within it an open loop amplifier that: (1) takes away from the available area to collect light (lowering the signal), (2) has varying gain and offset that creates Fixed Pattern Noise, (3) limits the operating speed of the pixel array, and (4) limits the ability to shrink the pixel to compete effectively against CCD’s. The bottom line is that APS Sensors must make tradeoffs between pixel size, resolution, image quality, and speed. For example, a high res. 14 MP+ APS image sensor operates at very low speeds. Small pixel APS Sensors operate at video rates but have poor image quality, and so on. See the ACS vs. APS primer for more information.
