A Decade of Vanguards, #2
Feb 5, 2010 12:00 PM, By D.W. Leitner
CMOS for professional cameras.
CCDs are wonderful. Aside from an occasional stuck pixel, they have proven almost perfect imagers. Stable, reliable, no image burn. So why have CMOS sensors become the darlings of digital cinematography? Complex CCD architecture and dedicated high-tech plants mean that only a few manufacturers such as Sony dominate the field and dictate who gets what. (Canon, JVC, Ikegami, Nikon, etc. don't manufacture their own CCDs.) CMOS, which has been around as long as CCDboth were invented in the late 1960scan be fabricated on integrated-circuit lines using conventional photolithography, a key reason today's inexpensive cell phones boast built-in cameras.
Operationally, CMOS has two significant advantages: 1) where CCDs gulp power, CMOS sips, and 2) since it's basically a large integrated circuit, each pixel can incorporate its own transistor for analog-to-digital conversion. Which is huge, because it means that CMOS readily performs tricks that CCD can't, such as enabling multiple "native" aspect ratios and outputting data in parallel streams for higher frame rates. You'll notice that compared to similar CCD models, CMOS camcorders run both cooler and much longer on the same battery charge. Kudos to Sony for leading the charge with such breakthrough CMOS camcorders as the tiny HVR-A1U and recent HVR-Z7U, and to Red Digital Cinema for proving that larger custom-designed CMOS sensors are ideal for digital cinema cameras.
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