Motion Blurring?

Silver · Post by **Silver** » 2003-03-27 02:54am

Not sure if a topic like this belongs in the OT forum, but most motion blurring I've seen is in either fantasy or science fiction, so I'll put it here for now. My question is this: what's the physical (scientific) explanation for motion blurring that we see? For example- in the Matrix during one fight we saw Agent Smith hitting Neo multiple times, and his arms were blurring when he did that. Another example would be in the anime series Inuyasha: when Inuyasha's older brother Sesshoumaru fights sometimes he'll leave behind "residual images" of himself, for lack of a better explanation, when he's moving around. Why does this happen? And also, are things like this "realistic" as in they could conceivably happen if somebody were moving quickly enough or something?

Mad · Post by **Mad** » 2003-03-27 09:22am

A camera takes a picture over a set amount of time to allow light to hit the film. If the object is moving over that time period, then the film will record the light from the moving object as appearing in multiple locations, hence the motion blur.

The same exposure time happens for the human eye, which is why you can see motion blur when looking at spinning fans or car wheels.

Sometimes motion blur is real (freeze-frame a scene from an old movie when a character rushes past the camera, the motion blur there is real), other times it's added to make the scene look better.

Those "residual-images" of something you see in anime don't happen, though. They're added simply for effect to make something appear really fast. At best, we'd see a big blur, or the object/person simply disappear. (Unless teleportation at FTL and distances in ranges of hundreds of thousands of kilometers are used, and even then...)

Post by **Darth Wong** » 2003-03-27 10:30am

Mad wrote:Those "residual-images" of something you see in anime don't happen, though. They're added simply for effect to make something appear really fast. At best, we'd see a big blur, or the object/person simply disappear. (Unless teleportation at FTL and distances in ranges of hundreds of thousands of kilometers are used, and even then...)

The only way to explain that bullshit is to imagine that the camera employs photographic superposition of multiple underexposed frames from film with a slow shutter speed. No reason why anyone would do that, but it's the only thing that works.