Understanding Color Sampling

When shopping for a video camera, color sampling is one faucet to consider. When shopping for a camera in July 2012, I noticed Canon touting their 4:2:2 color sampling features and so I wondered how big a deal this was.

In the article, “Understanding Color Sampling” by Barry Green, he states:

“You’ve seen the numbers: 4:2:0, 4:4:4, 3:1:1, 3:1.5:1.5, 4:1:1, 4:2:2… What does it all mean? And how does it affect your video? What’s better, what’s worse, and when does it matter?”

“What those numbers are referring to is a technique in digital video commonly called “color sampling.” The concept can be a bit confusing to those not used to working with video in the digital domain. In video, it’s common practice to not actually record all the color in an image, but rather to average the pixels together to cut down on the bandwidth. Color sampling is, in effect, a form of compression. The more compressed the engineers can make the color channel, the less bandwidth the signal occupies and the easier it is to record, transmit, or broadcast.”

In Barry’s article he does verify that 4:2:2 is much better than the alternatives, so Canon appears to have provided a higher end feature in some of their lower priced cameras.

Source: http://www.dvxuser.com/articles/colorspace/

On Canon's website, they state:

"4:2:2 provides ultra-fine transitions in tone and color and maintains the highest quality image for use in post production processes such as chroma keying, color grading, advanced compositing and effects."
Source: Canon XF 100 web page