CCD versus CMOS sensors

How do they compare?

A CCD (Charge Coupled Device) is a type of sensor.

CMOS (Complementary Metal-Oxide Semiconductor) is another type.

Each is a chip containing a grid-like field of extremely small, light-sensitive cells (photodiodes) which emit an electrical signal—converting light into electrons in proportion to the intensity of the light striking it.

These are the two most common types found in today's digital cameras. CCDs, considered the "standard" for most consumer digital cameras, have occupied the position of greater popularity.

Both types contain an array of light-sensitive cells that convert light levels (luminance) into corresponding voltage levels, but the differences lie in how they handle this conversion. The data captured on a CCD is read one row at a time, whereas a CMOS sensor handles the conversion much more efficiently and therefore more rapidly. It reads data from all cells at the same time.

CCD sensors are more costly to manufacture and therefore significantly more expensive. They also consume as much as a hundred times more power than a CMOS counterpart. CCD sensors tend to be of higher quality than CMOS sensors, and have a higher sensitivity to light. They result in comparatively low-noise images, whereas CMOS sensors are said to be more susceptible to noise. Having said that, though, improvements in CMOS technology have resulted in CMOS sensors being used in some high quality cameras to produce excellent pictures.