S2 & A620 low light video vs stills

[Chairman]

How come the S2 (and the A620) can take much brighter video than still shots at night under artificial light ? I tried turning the photo resolution down to match the video resolution but still needed shutter speeds up around 1 second to get stills that are as bright as the video.

I'm sure the video doesn't use a 1 second shutter speed :D

Gary