Stupid Question

[wahiba]

What is smooth motion?

If an object is moving quite fast then 18fps or 24 fps is not going to make much difference. similarly if something is moving very slowly.

I have videoed plenty of movement and never noticed lack of smoothness. Maybe it is like persistence of vision and we smooth it out in our minds, unless one is really looking for it.

Actually it is quite interesting how low one can get. something it is possible to test out on setting movies at different speeds on the computer. 12 fps seems to be the lowest that is still reasonable, even so 8 fps is not un watcheable.

[mattias]

<BLOCKQUOTE><font size=2 face="Verdana, Helvetica, sans-serif">quote:</font><table border="0" width="90%" bgcolor="#333333" cellspacing="1" cellpadding="0"><tr><td width="100%"><table border="0" width="100%" cellspacing="0" cellpadding="2" bgcolor="#FF9900"><tr><td width="100%" bgcolor="#DDDDDD"><font size=2 face="Verdana, Helvetica, sans-serif">What is smooth motion?

If an object is moving quite fast then 18fps or 24 fps is not going to make much difference. similarly if something is moving very slowly.</font></td></tr></table></td></tr></table></BLOCKQUOTE>

that's correct, but in any given situation 24 fps will look smoother.

<BLOCKQUOTE><font size=2 face="Verdana, Helvetica, sans-serif">quote:</font><table border="0" width="90%" bgcolor="#333333" cellspacing="1" cellpadding="0"><tr><td width="100%"><table border="0" width="100%" cellspacing="0" cellpadding="2" bgcolor="#FF9900"><tr><td width="100%" bgcolor="#DDDDDD"><font size=2 face="Verdana, Helvetica, sans-serif">I have videoed plenty of movement and never noticed lack of smoothness.</font></td></tr></table></td></tr></table></BLOCKQUOTE>

video uses 50 or 60 fps and a 100% duty cycle, that's why.

i also used the expression persistance of vision before to describe why we see a series of stills as motion, but somebody explained that the motion is created in the brain, while p.o.v. is a "slowness" in the retina that evens out flicker above certain frequencies. i wouldn't be surprised if these two phenomenon work together though...

/matt

[MovieStuff]

<BLOCKQUOTE><font size=2 face="Verdana, Helvetica, sans-serif">quote:</font><table border="0" width="90%" bgcolor="#333333" cellspacing="1" cellpadding="0"><tr><td width="100%"><table border="0" width="100%" cellspacing="0" cellpadding="2" bgcolor="#FF9900"><tr><td width="100%" bgcolor="#DDDDDD"><font size=2 face="Verdana, Helvetica, sans-serif">Originally posted by mattias:

running one of those at 50 fps would surely look very much like video</font></td></tr></table></td></tr></table></BLOCKQUOTE>

Agreed. In fact, anyone with an Elmo or Goko viewer that has a prism shutter can see the effect themselves by rewinding some film through the gate at high speed and watching the resulting image. Looks justs like video.

Roger