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Re: Real Time Steady Gate



On Oct 21, 23:23, smcw at onramp.net wrote:
} Subject: [TIG]  Real Time Steady Gate

> Is there still a need to 'Steady-Gate-transfer' film which is intended for
> effects and compositing, or have the later Ursa Golds and Spirit done away
> with the need for steady gate?

that's a good question Steve, and I'll summarize here what I know, and
ask for more from those who can fill in the gaps in my knowledge.

On Cintel machines, I've used four systems: Steadi-Gate (pin
registered non-realtime transfer), RTS (Real Time Steadigate), Pin-Up
(a gate that does realtime non-steadi transfer and non-realtime pin
transfer), and JumpFree (Cintel's 'real time' steady transfer gate).
The first three are third-party systems.  

I've not worked on PinUp for a long time, and ask that anyone who has
recent experience with it please contribute here.

The effectiveness of Steadi-Gate pin registration systems is almost
entirely a result of engineering setup.  I've worked on systems that
were excellent, and systems that were less steady than realtime
transfer done on an RTS gate.  RTS and JumpFree can be very
effective-- the RTS system in one telecine suite where I worked was
extremely close to the specification from the top pin gate in use at
that company at the time (but this difference was occasionally
worth using the pin gate; see below).

On the Spirit, steadiness appears to be outstanding and on a par with
the realtime systems I've used on Cintel machines.  I'm aware that a
pin registration system has been in development for the Spirit- is it
in use?  Perhaps someone here will enlighten us.

I've seen in the last few years a progression away from doing
(non-realtime) pin registration, and toward using RTS or JumpFree
systems.  These are supplemented nicely by the steadying capability of
the Henry or Flame... the question of using non-realtime pin
registration for transfer now has been, in my recent experience,
determined by: 1) the client's comfort with realtime systems 2) the
client's comfort with the compositor's ability 3) the time and budget
for the job 4) the number of layers as shot.

The best pin registration system, on a Cintel machine, will outperform
the best realtime system, but in some cases not by much, and this
difference may not be discernible in the final composite.  However,
for some multi-layer composite jobs, the best pin registration systems
I've used (and as I mentioned, these differ markedly from machine to
machine, given the same models of telecine and gate) show this
difference to be worthwhile.  

example: motion control shot of starship flying through space.  Pass 1
from camera is over green screen; camera pass 2 is exposed for the
running lights on the ship; camera pass 3 is exposed for shadow
detail.  Pass 2 contains tiny, individual windows, which will need to
match perfectly those on pass 1 and 3...  the smallest error in
registration will affect the composite.  Assuming the camera is as
close to perfect as possible, the accuracy of the telecine's pin
registration will determine the quality of the composite, unless and
until the compositor intercedes with steadying of his/her own.

additional questions: is the job thousands of feet of film, or is it a
few takes of one shot?  Is the job a live action on green screen, with
background and animation to be added later, and with no static,
reference, foreground objects (if this is the case, probably the green
screen element can be transferred on a realtime registration system).
What are the budget ramifications of spending hours correcting the
steadiness in Flame, versus spending the time in telecine?

Sometimes there are multiple solutions for the questions, one will
work as well as another, and the only differences will be money and
time spent.

Rob Lingelbach
Senior Colorist, Filmworkers Club Dallas

-- 
Rob Lingelbach     | "I would give nothing for that man's religion
rob at alegria.com    |  whose very dog and cat are not the better for it."
www.alegria.com            --Rowland Hill, "Village Dialogues"

---
Thanks to Glenn Eason of Hillcrest Engineering for support in 1998.
No product marketing allowed on the main TIG.  Contact rob at alegria.com
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