CCD vs CMOS

Diffen › Technology › Consumer Electronics › Cameras

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.

Comparison chart

CCD versus CMOS comparison chart
	CCD	CMOS
Acronym	Charged Couple Devices	Complimentary Metal Oxide Semiconductor
Cost	More expensive	Cheaper
Shutter type	Global	Rolling
Skew	No	Yes
Wobble	No	Yes
Partial exposure	No	Yes
Vertical smear	Yes	No
Noise	Less	More
Power efficiency	Less efficient	More efficient

A CMOS image sensor inside a camera

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.

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.

A CCD sensor on a circuit board.

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.

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.

Reliability

Although CCD used to be more reliable than CMOS, there is currently no difference between the two sensor types in terms of reliability.

Popular Cameras

CMOS cameras are more popular — only two of the top 15 best selling cameras on Amazon use CCD sensors.

References

About the Author

Nick Jasuja has over 15 years of technology industry experience, including at Amazon in Seattle. He is an expert at building websites, developing software programs in PHP and JavaScript, maintaining MySQL and PostgreSQL databases, and running Linux servers for serving high-traffic websites. He has a bachelor's degree in Computer Science & Engineering.