Slow motion

[J Costantini]

Hi.

If I had to shoot a scene using the 60i mode on the ag-dvx100 and wanted it on slow motion (in post), would it help to use a shutter speed faster than 1/60? Would it preserve the quality better?

 

Thanks

[David Mullen ASC]

A film camera running at 60 fps with a normal 180 degree shutter would have a shutter speed of 1/120th of a second, so if you convert a 60i recording to 60 fps but use a 1/60th of a second shutter speed, the motion will look smearier than it would with a film camera running at 60 fps. So use a shorter shutter speed, like 1/100th or more.

[Jon Allen]

I'm not going to argue with Mr Mullen about how to light and all, but really the only way to get any sort of slow motion out of a dvx100 is to record onto tape at 60i, then import and convert to 50%, then run a deinterlacer. Now you have appx twice as many frames recorded. Granted, the quality is lower because you're basically halfing the vert rez.

So how do you make it higher quality? Get a wind-up camera that you can set framerate on.

What's the big deal with slow motion anyway?

[David Mullen ASC]

Yes, shooting at 60i and converting it to 60 frames is a typical solution -- the question is what shutter speed to set the camera at. I've found it looks a little odd to use 1/60th because the motion looks too smeary after it is slowed down (I did it on "D.E.B.S." so I wouldn't have to boost the light levels for slo-mo but now I wish I had used a faster shutter speed...) No free lunch basically.

[John Sprung]

David found a 360 degree shutter to be too smeary. But also beware of going too far in the other direction. Motion blur is necessary. Without it, there is no illusion of motion, just an annoyingly fast sequence of still images. So, it's best to stay around 180 degrees with the shutter, or 1/120th sec. at 60 fps.

 

 

 

-- J.S.