Short Description
Image Sensor
Photo of a Canon CMOS
sensor
The sensor type refers to the semiconductor design/arrangement of the image sensor. There are a wide array of
different types with each manufacturer making its own adjustments to their design. Furthermore over time the
designs are revised and improved. That being said there are two main types of sensors: CCD and CMOS.
CCD
CCD or charge coupled device sensors are essentially tiny arrays of photoactive regions on a chip, each region
reacts to light and converts the intensity into a electric signal- this permits each CCD to convert the light
focused on it to a matrix of light intensities, coupled with a colored film that filters the light into red, green
and blue (using a
Bayer pattern) the CCD is able to produce an array of
pixels each representing a different color. CCDs produce slightly worse quality images than CMOS sensor although
the difference is not significant.
Great Affordable CCD Digital Cameras Under $500
Here is a list of some of the top CCD based sensor cameras.
CMOS
Top CMOS Camera
The
Pentax K-5 is the one of the best CMOS sensor cameras.
CMOS sensors utilize what is referred to as an active pixel sensor and consume less power, have higher noise
immunity and have less lag than a CCD. They also permit more integrated designs which can cut down on noise gain
and provide the opportunity for a cleaner image. Although most CMOS sensors use a
Bayer pattern to determine the RGB values of the image there
are other options. Sigma's Fuveon X3 sensor does not use a Bayer pattern and thus does not require the demosiacing
to produce its image, consequently it has many advantages and produces images of much higher resolution and quality
then the name plate resolution would indicate - typically equivalent to a Bayer generated image of twice the rated
resolution.
Great Affordable CMOS Digital Cameras
Here is a list of some of the top CMOS based sensor cameras.
Discussion
Showing 13 comments
Because of their origins in the computer chip industry, CMOS chips are cheaper to manufacture. But in general, a camera equipped with CCD will produce a better quality image with less electronic noise than a CMOS chip.CCD sensors, as mentioned above, create high-quality, low-noise images. CMOS sensors, traditionally, are more susceptible to noise.
Because each pixel on a CMOS sensor has several transistors located next to it, the light sensitivity of a CMOS chip tends to be lower. Many of the photons hitting the chip hit the transistors instead of the photodiode.
CMOS traditionally consumes little power. Implementing a sensor in CMOS yields a low-power sensor.
CCDs use a process that consumes lots of power. CCDs consume as much as 100 times more power than an equivalent CMOS sensor.
CMOS chips can be fabricated on just about any standard silicon production line, so they tend to be extremely inexpensive compared to CCD sensors.
CCD sensors have been mass produced for a longer period of time, so they are more mature. They tend to have higher quality and more pixels.
Based on these differences, you can see that CCDs tend to be used in cameras that focus on high-quality images with lots of pixels and excellent light sensitivity. CMOS sensors traditionally have lower quality, lower resolution and lower sensitivity. CMOS sensors are just now improving to the point where they reach near parity with CCD devices in some applications. CMOS cameras are usually less expensive and have great battery life.
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Yes, I've been seriously considering switching to the Nikon d700 based on the available stuff regarding its autofocus capability in general, and in low light... I just don't dig their body design nearly as much, so we'll see. Thanks again!
I know that conflicts with what you're seeing, but DXO's tests are showing even they don't think the 40D does much better :) But, if you compare the 40D to the Nikon D700 which is full frame, has a huge advantage, getting the same quality images at 2300 ISO that the 40D gets at 700 ISO.
We're often most interested in low light (high ISO) image quality, and the M9 doesn't do well for a full-frame sensor, in fact many APS-C sensors (like the D90) do better. See D700 vs M9 for a full frame vs full frame CMOS vs CCD comparison.
The only reason CMOS is used in big cams is because you can afford more sensor size for the same money.
At least this is what was been told in the past. CMOS might have evolved quite a lot, and there are view good cams with CCD sensors since CCD seems not to be able to use LiveView, drain a lot of power and are expensive.
*The* main cam using CCD is the Leica M9. And some attest the image quality to be better than most fullframe DSLR (luminous landscape, for example).
We've been basing our conclusion on the fact that the DSLRs with the best low light performance have CMOS sensors. This article: http://www.brayebrookobservatory.org/BrayObsWebSite/HOMEPAGE/DSLR_CMOS_vs_CCD_SENSOR.html doesn't really seem to draw a conclusion either way, but backs this up that the DSLRs today that use CCDs are not as good as the DSLRs that use CMOS when it comes to low light noise.
http://ezinearticles.com/?CCD-VS-CMOS-Cameras&id=4937357
http://electronics.howstuffworks.com/cameras-photography/digital/question362.htm
http://www.1people1camera.com/2009/04/22/ccd-vs-cmos-image-sensor-comparison/
http://www.dalsa.com/corp/markets/CCD_vs_CMOS.aspx