CMOS and CCD image sensors convert images (light) into electronic signals. CCD sensors are slightly cheaper and are the older, more mature technology. CCD and CMOS sensors are susceptible to different problems — CCD sensors are more susceptible to vertical smear from bright light sources, while CMOS sensors are susceptible to skewing, wobbling and partial exposure. However, neither technology is a clear winner over the other in over all image quality.
edit Shutter Differences - Global vs. Rolling Shutter
CCDs use a global shutter, which exposes the entire image simultaneously. This can lead to blur if any motion occurs in the image during exposure, but a high shutter speed prevents this problem.
CMOS sensors are equipped with “rolling shutters,” which expose different parts of the frame at different points in time. This can lead to skew, wobble and partial exposure in photographs.
In well-lit conditions, the differences in shutter mechanisms do not cause any problems. However, in low-light areas, or under slow-flickering lights, a dark bar may appear rolling through your footage (in case of video recording) with a CMOS sensor. Another risk is the picture may appear split into a dark and bright half when using a flash.
edit Vertical Smear
CCD sensors are more susceptible to vertical smear from bright light when the sensor becomes overloaded, while high-end CMOS sensors do not suffer from this problem.
edit Performance of CMOS vs CCD sensors
CCD sensors create high quality images with low noise (grain). They are more sensitive to light. However, CCD sensors consume around 100 times more power than equivalent CMOS sensors.
CMOS images tend to have more noise and need more light to create images at the proper exposure. However, CMOS sensors are much more power efficient, leading to longer battery life, and as they are moving closer to CCD in quality over time.
edit How to choose
CCDs are preferable when you want to focus on high-quality images with many pixels and need excellent light sensitivity. CMOS sensors are preferable for high speed cameras, as they scan and offload their footage quicker.
Although CCD used to be more reliable than CMOS, there is currently no difference between the two sensor types in terms of reliability.
edit Popular Cameras
CMOS cameras are more popular — only two of the top 15 best selling cameras on Amazon use CCD sensors.