wrote in message
...
On Fri, 17 Jul 2009 08:41:04 -0700, "charlie"
wrote:


wrote in message
. ..
On Fri, 17 Jul 2009 08:14:20 -0700, "charlie"
wrote:


"Smitty Two" wrote in message
news In article
,
DerbyDad03 wrote:

On Jul 16, 12:57 pm, Smitty Two wrote:
In article
,

DerbyDad03 wrote:
I have not been able to find an on-line copy of
the commercial.

snip

when I run my DVR in frame-by-frame mode, it still
appears that the drill and bit is rotating in reverse.

Step up to the plate in the name of science, and be the first to
post
your clip online.

I don't have a "clip".

I rewound the DVR while watching the show and stepped through the
commercial to see what it looked like in slow motion. I did not
record
the show.

Ah, sorry, I'm DVR impaired.


That said, I'm still looking for an answer to my question: Would the
wagon wheel effect be captured while filming the commercial and thus
be captured by my DVR or is the wagon wheel effect "perception" in
all
cases?

I'm not sure that I understand your question, and I'm not sure that I
could answer it if I did ... seems we're down to you, me, and harry
on
this one so we'll see whether we all have enough interest in the topic
to keep ferreting things out.

if you look at video camera specs, they all have a "shutter speed" even
though there is no real shutter. that's the rate the computer can poll
the
video chip, as it has to poll almost every location at very close to the
same time or you'd get smearing of the video picture.

thus, a video or film camera would still show the same phenomon of
strobing
on rotating parts.

regards,
charlie
cave creek, az


Incorrect.

The strobing on rotating parts is visible due to the difference in
frame rate (shutter speed) and the timing standard frequency of the
video equipment. IOW film played back on a TV set.

please reread for comprehension. you basically restated what i said. the
question was whether a video camera rather than a film camera would cause
the problem, and the answer is yes, as they both have "shutters"


No, you are missing a vital piece of the puzzle. All faux shutter
speeds in a video camera are based on the 60 cycle standard. Film
cameras do not use that standard for shutter speeds.

If you use a film camera to film the screen of a TV, the screen on the
TV will appear to roll for this reason.

why would a digital video camera, running on dc internally, have a standard
based on 60 cycles?

http://www.mediacollege.com/video/camera/shutter/
http://www.videomaker.com/article/10418/

in reality, it doesn't. typical video shutter speeds are between 1/1000 to
1/2000 second.

the display on a tv is based upon 1/2 of the ac line current. that has
nothing to do with the shutter speed of the camera.