What's the point changing the shutter speed when recodring movies?

When manually adjusting the exposure setting for movie recording like aperture and ISO, I also noticed there is a shutter speed adjustment. The shutter is always open when shooting a movie so what is the point of the shutter speed?

I read the manual and I still don't get it. The manual also says the faster the shutter speed the less smooth the subject's movement will look. If the shutter is always open when recording a movie, how does the shutter speed affect the smoothness of the video?

http://www.vimeo.com …tting-the-record-straight
There you go

BrickR wrote in post #12754238
http://www.vimeo.com …tting-the-record-straight
There you go

that's a pretty informative video, thanks

garycoleman wrote in post #12754265
that's a pretty informative video, thanks

Yes indeed, Very. I had no idea. Haven't messed with my video as much as I would like. Until now. Thanks for the info.

I always thought it was the same but not anymore. Thanks for the video.

After watching more videos and doing some reading, the best ISOs to use are 160, 320, 640, and 1250.

ISO 160 has less noise than ISO 100
and ISO 640 has less noise than ISO 500

http://vimeo.com/23082​874