Image Sensors
Image sensors are more than just about mega pixels. The Digital Photo Pro posting All About Image Sensors
(From: Digital Photo Pro)
There’s clearly a lot of amazing technology packed into a sensor—things like microlenses and color filter arrays and anti-blooming gates—but it’s easy to ignore how it works. Understanding the technology provides a better understanding of the image-making process and can lead to better decisions in choosing and using a digital camera.
There are two primary types of sensors used in digital cameras today: CCD (Charge-Coupled Device) and CMOS (Complimentary Metal Oxide Semiconductor). Often thought of as 21st-century innovations, they were actually developed in the 1960s and immediately shaped the digital revolution—CCDs in astronomical and scientific uses and CMOS in everything from cell phones to computer RAM.
For the foreseeable future, it appears that CCD and CMOS technology will coexist and that the rapid improvement of each will continue. As Olympus’ Pelkowski says, “There is still going to be a tremendous amount of evolution in chip technology. It’s very difficult to tell which way it’s going to go. You never know. There could be new technologies that come out that are going to completely blow away what now exists.”
An interesting development closely coupled to image sensors is the increasing size of the analog to digital converter, the electronics that converts sensors analog data to digital, from 12 bits to 14 bits. Instead of (4,096 Red x 4,096 Green x 4,096 Blue =~ 64 billion) possible color values with 12 bits, the 14 bits deliver 64 times a many color values (64 billion x 64 =~ 4 trillion) possible color values.
By the way, if you’re shooting JPEG instead of RAW, the number of bits used is just 8, which means there are only ( 256 Red x 256 Green x 256 Blue = ~ 16 million) possible color values.
…John
