"Tek" <tek### [at] evilsuperbraincom> wrote:

> Interesting. I've played with similar things on a realtime motion blur effect a
> few years ago. I assumed the shutter time could be adjusted (to control exposure
> as well as motion blur, much like the aperture does for focal blur) but I never
> actually researched what real cameras do. Is it always 50%?

In a general sense, yes. (Although, as you say, cinematographers are always
fiddling with shorter exposure times, for effect--that is, an open shutter
*less* than 180-degrees. Pro film cameras have this variable feature. The D-Day
landing sequences in SAVING PRIVATE RYAN would be a good example of such an
effect; the image frames seem to be almost devoid of motion-blur, kind of a
jittery strobe-like quality.) At the other extreme, I think there are some pro
cameras that may have as much as a 220-degree open shutter--certain
models of Panavision or Arriflex, possibly. My guess is that they are more
useful in low-light situations. Or simply to impart *more* blur per frame, for
whatever artistic reason.
>
> The thought occurs that you might get a more film-like effect if your first
> and last sub-frames had a gradient to black on them, to simulate the blur of
> the closing shutter! But I'm probably over-thinking this.

I was thinking about that too! Wondering (in a theoretical sense only!) how to
reproduce it. You're idea sounds like it might just work.

BTW, the 'skip-action' code that I posted seems kind of sloppy, now that I look
at it again. :-(  I should have cleaned it up a bit.

Ken

Post a reply to this message