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Introduction
Camcorder Survival Kit
Maintenance Key With Metal Tape
Avoiding Head Clogs
Ikegami/Avid's Disk Recording System
Matchmaker,
Matchmaker
A Call for Uniformity
The Ultimate Camera Standard
Looking Your Best
Video Head Evaluations
Sony Investigates Betacam Camcorder Headwear Problems
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Matchmaker, Matchmaker
By Mark Bell
Our field is like many where
technology and technique leapfrog as time goes by. At this particular time,
it's the two- camera shoot that is becoming more popular, and two cameras at
the same location need to match if the production is going to look as good
as possible. While today's CCD technology offers easy set-up, different
camera models from even the same manufacturer can pose a problem when it
comes to getting pictures to match on a simple two-camera shoot.
Some companies have, or have had, a camera set-up/shading standard. Some
techs just do it by experience, which may mean that nobody ever told them to
work in conformance with a particular standard. In today's market there are
many shops, and the likelihood of one standard being observed in any two
separate shops has proven to be small.
Some companies provide crews with a video technician, others assemble crews
without a tech and rely on various independent shops for camera set-ups and
maintenance. Needless to say, an on-site tech is the way to go, but not
always provided for in this tight-budget world.
In this world, non-uniformity of set-up standards translates into post
production time and expense, as organizations are spending time in post
production color correcting before actual editing is started. There's no
reason that this extra step is needed if it can be eliminated up front.
A Call to Arms
From the very diversified experience of Macie Video Services in Dedham, MA,
Roger Macie expresses the following: "There is a call to fill the need of
both sides of the camera market [camera person and client] to create a de
facto standard that can be set up away from location and be equal, or at
least very comparable, on sight, without on-site adjustment."
In other words, we need to have a uniform national standard. One person from
one area of the country should be able to meet with one from another and
have a match much closer than is routinely observed.
"It's a huge problem," continues Macie. "From my clients, I hear frequently
of situations that demonstrate the need for a standard. It amazes me how
many cameras seem not to be set up to any standard with consistency when I
get them into the shop."
According to Macie's experience, gammas and flare compensation are two
adjustments critical in matching. Flares, for instance, are frequently not
set correctly. One quick telltale sign of this can be seen while a camera is
pointed at a "pure" white chart with an "absolute" black reference in the
center. If the pedestal moves consistently more than a few units while
opening and closing the iris through its range, flares should be adjusted.
While researching this article, it was observed that a clear filter, with
coating imperfections due to wear, caused a remarkable change in flare
performance, showing the need to use top-quality optical equipment. Any
changes in lens components after set-up may affect flares and therefore,
matchability on site.
Gammas are simple enough to see on any standard chart, but what is tough to
see is consistency in gamma level setting from one camera to the next.
Another interesting point of note is that the traditional 7.5 unit pedestal
is not well-suited for today's cameras, as 7.5 tends to clip some of the
signal. Pedestals of 8.5 and higher are becoming typical, but so far there
is no real standard for this "new" setting.
Practical Solutions
Macie is experimenting with DSC's rear illuminated charts, also called
"Optical Signal Generators" by the manufacturer, to study the implementation
of a standard. The rear-illuminated charts provide a consistent level of
light, without reflection. Macie has had a lot of success with this system
and is looking to expand its use in seeking a standard.
Another reason to use the "Ambi-illuminator," according to Macie, is that
it's the only chart that can provide a stable reference for color matching
matrix adjustments. The term "optical signal generator" is accurate in terms
of how it allows for a reproduction of a standard bar's test signal on
waveform, vectorscope and video monitors through a camera's optics.
"The charts allow me to be very specific when making color adjustments."
Macie adds.
A second method of creating a uniform set-up environment is used by Steve
Finer of Finer Associates in Watertown, MA. He had similar feelings about
light source consistency and uses Sony's "light box" to obtain what he feels
are his "Finer" results.
"Starting with a calibrated uniform light source is probably the most
important step," Finer offers. "You can take any of the cameras I have
worked on, put them side by side and they will match. The newer cameras
don't drift like older models. If not [field-adjusted] they should stay
pretty much as set up in the shop."
There are opinions that rear-illuminated charts or light boxes may not
properly reproduce test patterns. For this reason, some technicians shy away
from any rear-illuminated concept.
S.H. Traditional Method
Brad Reed, a veteran operations and maintenance professional associated with
Broadcast Technical Group of Hopkington, MA, is a traditional chart person.
He prefers to use the standard Porta-Pattern charts for set-up.
"I've seen a lot of projected image devices," Reed says, "and don't feel
comfortable with the transfer characteristics versus the standard charts. If
kept clean, taken care of properly, and renewed if faded, the chart is a
proven method.
"Many times a camera set up in the shop does not look good in the field, and
needs adjustment, right then and there. Charts are easy to carry along and
fairly inexpensive compared to projection devices."
But this leaves us with three different devices to perform the same task.
Each technician has a solid opinion and makes the adjustments he or she
believe are in the best interest of the camera, the client or the job.
There is an acknowledged need for uniformity. We've evolved to a point where
a new standard is needed for field gear, as crews come from all over the
place and their various shading values are "all over the place" as well.
Without a video engineer on a crew, a show may be condemned to cost more in
post.
Uniformity Needed
While the concept of a new uniform standard sounds "perfect
world"-applicable, it may not sit well with everybody, just like the present
standards do not.
Frank Governelli, Director of Bureau Operations for CBS, is very aware of
the situation with mismatched camers. He confirms his awareness of the
situation and offers some perspective which may speak for many.
"Some of our freelance people come into our shop so we can set up their
camers to our standards. However, many shows still have built-in set-up time
for color correction before post so we can get the tapes where we want them
to be. In terms of a national standard though, we have to ask ouselves, 'Do
we want to look like everybody else?'" |
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