[Tig] Vialta?

Martin Euredjian ecinema
Sat Feb 23 21:47:59 GMT 2002


From: "Sebastian Sylwan" <sebastian at vrmmp.it>

> Why would you need to rotate your image in between two "for compositing"
> scans ?

> Secondly, in my experience, the Vialta stabilizer system works mainly in
> vertical stabilizing, whereas horizontal is mainly done mechanically.

Rich mentioned that the problem is exhibited in rotation, pan, tilt and
zoom.

Clearly there is a need for repeatability when performing these operations.
Perhaps not from a purely "laboratory" technical perspective.  In other
words, I can see an engineer in a lab say "no big deal, put up a reference
frame/chart and adjust accordingly".  However, from an operational or
process-flow vantage point repeatability of settings is paramount to
enhancing the profitability of the process.  It really depends on the type
of work being done, but, in general terms, if a Colorist cannot count on
repeatability and this is a requirement for the job the net result will be
that time will be wasted ensuring that he/she gets back to where the framing
needed to be every time a change is made.  So, putting my business hat on, I
say that the lack of repeatability can result in a higher cost of operation
for a certain class of jobs.

How about real-world examples of where there might be an issue with
repeatability.  I can think of a few (by no means a complete list):

1-  Film checks during a job.  Sometimes an engineer will be called in to
troubleshoot a problem.  Perhaps ascertain if there's a transport stability
issue (vs a rare in-camera problem) or if the film is damaged, etc. etc.  A
common technique is to zoom out, pan around or even rotate in order to look
for various clues as to what may have caused the problem.  If the various
framing controls cannot be trusted to return to the desired "home" position,
a re-alignment procedure must follow any such modifications of framing.
This might involve rolling the film back to a known frame (one that is saved
in a still store) and checking/modifying the framing, or, as the worst case,
the taking-down of the roll in order to put-up a framing chart and start
over.  That is a waste of time and this is a very likely scenario.

2-  Critical framing.  A very specific framing is requested by a client.
Any exploration (for example, panning a bit to the right 'cause a main
character was cut in half during a particular take) would result in a need
to go back and re-frame to a chart.

3- Client supervised work.  Music videos, commercials, even long-form work.
Murphy's law says that a client will most certainly make you zoom, pan,
tilt, and rotate all over the universe.

4- Commercials.  There's nothing conventional about this work.  The lack of
repeatability can be quite painful and costly.

The good news is that it sholdn't be a bit deal to fix this.  Very high
precision electro-mechanical-optical assemblies fall into the realm of very
well known technology and, for a company with the financial and technical
resources that Sony has it shouldn't be a big deal to make this
repeatability problem go away.  At least that what I think.  I could be
wrong.

Martin Euredjian
eCinema Systems, Inc.
(661) 305-9320
ecinema at pacbell.net








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