With all the excitement coming from the Canon announcement this afternoon (updated rumor from canonrumors.com), I thought it would be helpful to discuss a bit about sensor sizes and why they're important in shooting stills as well as video. Rumors are that today's video cameras will have a ‘super35' size sensor – which is just a bit bigger than the Canon APS-C sensors (the Canon EOS 7D, 60D and others have that size) but the same size as other cameras recently in the video market like the Sony F3. Note the Panasonic AF-100 is a micro 4/3 camera for an additional comparison.
Demo from LensProToGo
I found this demo from the folks over at LensProToGo and tho the ending shows an example of the depth of field difference in stills, you can certainly extend that to video.
A tutorial demystifying the concept of different sensor sizes in modern day dslr cameras.
Sensor size chart
And, what better way to see the differences in the sensor sizes than a chart from wikipedia?
We obviously don't care about the medium format size in the chart above, but it helps to see the APS-C size (don't know why this chart didn't show the super35 size) and the smaller current senors like the micro 4/3rds. Actually, here's a better chart that shows the digital video sensor sizes from creativecow:
There's also a good article by Matt Jeppson on the AF100 sensor size comparing it to others.
(cover photo credit: snap from the video)