The sensor on the 5D is huge. Here's a graphic with most of the current video camera sensor sizes: http://rebelsguide.com/dl/sensorSizes_06_cheatSheet.png http

The sensor on the 5D is huge. Here's a graphic with most of the current video camera sensor sizes: http://rebelsguide.com/dl/sensorSizes_06_cheatSheet.png http://rebelsguide.com/dl/sensorSizes_06_cheatSheet.png A bigger sensor means that it can operate well at very low light levels. Also note that at $2500 this is by far the cheapest option for shooting feature quality films. There are some issues with audio, so you will have to record it using an external recorder, but with a nice mount, this is an amazing camera.