Updated:
2002
New
Insights in an Ongoing Debate:
Film vs. Videotape
Which
is better: film or videotape?"
First, we need to acknowledge the fact
that this is a controversial subject, especially in Southern California,
the "film capital of the world." (If you want to quickly get
thrown out of a Hollywood party, just start talking about how
video is superior to film.)
The fact is, each is superior in a number of ways; it depends on your
needs. And we also need to acknowledge the fact that much of the
information about the "inferiority of video" is no longer
valid. (Even so, old beliefs persist.)
Let's look first at the advantages of
film.
Advantages of Film
Since
the TV Production modules concentrate on television, we tend to emphasize
the advantages of video. But someone is bound to ask: "Why is most
dramatic television shot on film.''
There are several reasonsstarting
with the historical.
After more than 100 years of 35mm film
production, a rich and highly sophisticated tradition has grown up around
film. Unlike video production where newcomers may quickly find themselves
functioning as camerapersons and even in some cases as directors, the
feature film tradition typically involves a long, highly-competitive
apprenticeship which can extend over many years.
Less motivated people tend to drop out
in favor of those who are more talented, persistent and dedicated.
Because
of rich heritage of film, the production and postproduction processes
have not suffered from a lack of talent or supporting industries. In
Southern California alone there are thousands of companies that specialize
in various aspects of film production.
Comparing the closing credits of a major
film feature with those of a typical video production provides some
measure of the differences that still exist between the two media. (Try
sitting through the closing credits of Independence
Day or
The Titanic!)
For decades film has enjoyed consistent
worldwide standards. A 16mm film can be broadcast on any of world's
broadcast systems (regardless of the broadcast standard) and a 35mm
film can be shown in almost any theater in the world.
Video, on the other hand, has not only
progressed through numerous tape formats, but there are now a half-dozen
incompatible broadcast standards being used in various parts of the
world. For producers with an eye on international distribution, film
has been the obvious choice for decades.
With the move to HDTV producers have
seen in film a way of covering all of the bases: having a medium that
can be used with in any of the SDTV, HDTV world standards.
Technical Quality Compared
It
is commonly believed that the quality of 35mm motion picture film
(as viewed on television) is better than video. If we are talking about
the artistic differences, then film has a definite advantage—for the
historical reasons we've noted.
But as more and more film-style, video
production is being done, especially in single-camera HDTV/DTV, this
gap is disappearing.
Although artistic differences between
film and videotape are difficult to measure, purely technical differences
are not. This brings us to the following statement.
If production
conditions are controlled and if comparisons are made solely on the
basis of technical quality, the best 35mm film will be slightly inferior
to the best video—assuming the latest professional-quality video equipment
is used and final result is broadcast.
As controversial as this statement might
be with film people, the reason becomes obvious when the production
process for each medium is traced.
First,
it is important to realize that if a signal from a video camera is recorded
on the highest-quality process, no discernible difference will be noted
between the picture coming from the camera and the picture that is later
electronically reproduced.
With film intended for broadcast the
process is far more complex.
First the image is recorded on negative
film. The original negative film is used to make a master positive,
or intermediate print. From the master positive a "dupe'' (duplicate)
negative is created; and from that a positive release print is made.
This adds up to a minimum of three generations.
At each step things happen: subtle color
and quality variations are introduced by film emulsions and processing,
there is a general optical degradation of the image, and the inevitable
accumulation of dirt and scratches on the film surface starts.
After all of these steps, the film release
print is projected into
a video camera to convert
it to an electronic signal—which is where the video signal started out
in the first place.
To understand the film-video difference
we must also bear several other factors in mind. Film is capable of
resolving several times more detail than standard video. But since it
looses much of its sharpness in its route from film camera to television
camera, image enhancement is used when the film is converted to video.
Although image enhancement sharpens the
overall look of the film image, subtle details, once lost, cannot be
enhanced back into existence.
But sharpness
isn't everything.
Many people think the slightly soft look
associated with film on television is actually one of its advantages.
The soft ambiance surrounding the film image is subconsciously if not
consciously associated with "Hollywood film making.''
At the same time the slightly sharper
image of video is associated with news and the live coverage of events,
subject matter very much in contrast to the normal fare of feature films.
There
is also a less obvious difference. With NTSC television the film-to-video
conversion process requires some technical "fancy footwork"
that results in the introduction of almost subliminal effects
associated with the film image on TV. (Recall that the NTSC standard
is used in the U.S., Canada, Japan, and several other countries.)
NTSC
video is transmitted at 30 frames per-second and film is recorded at
24 frames per-second. (The machine shown on the left converts
film to video.) Since there is no nice, neat math associated with
dividing 30 by 24, the only way to make the conversion is to regularly
scan some film frames twice.
This results in a subtle high-speed jitter,
a type of artifact has become associated (if only subconsciously) with
the film image on TV.
Incidentally, all of these film-video
differences can (and have been) electronically duplicated with video—right
down to the random specks of dirt associated with film!
With
the SECAM and PAL broadcast standards used in non-NTSC countries the
conversion process is easier. Both of these systems operate at
25 frames per second—very close to the 24 fps used in film. Even
when projected, the 1 fps difference is almost impossible to detect.
If the film is intended for broadcast,
adjusting the film camera speed to 25 fps is a common solution.
Thus, non-NTSC systems—the systems used
in the majority of countries—have an easier time making the film-to-video
conversion.
Film is Suited to the High-Definition Systems
A
major advantage of the film
image is associated with the need to convert programming to digital
video and HDTV. The old NTSC video images are limited by the
NTSC process. Trying to convert them to HDTV and digital images
only magnifies the limitations of the NTSC system.
However, productions shot on film can
be readily converted to the higher resolution formats and take full
advantage of the increased resolution. And film originally shot in a
wide-screen aspect ratio has an added advantage when converted to the
16:9 HDTV aspect ratio.
Interestingly, with the advent of high-definition
video, we're seeing more video-to-film conversions—productions shot
in a high-definition video standard and then converted to film.
In some tests digital video has been converted to 35mm film and projected
in a theater. Under test conditions audiences were hard-pressed
to discern a quality difference.
In 1999, theaters experimented with using
video projectors for showing feature films. Not only is there a great
cost savings associated with this approach, but since material is delivered
via a satellite link, live sporting events, rock concerts, etc. can
also be featured.
As video projectors improve even more
and costs come down, we will undoubtedly see theaters convert to video
projection.
Coping With Brightness Ranges
Until
recently, video cameras simply could not handle the brightness range
of film. (Remember the 30:1 brightness range limitation of video?)
If film exposure is carefully controlled,
a bright window in the background of a scene, for example, will not
adversely affect the reproduction of surrounding tones. With the limited
brightness range associated with tube-type
video cameras the same
bright window would significantly darken surrounding tones. (This same
problem crops up with consumer and prosumer equipment that rely on automatic
exposure circuitry.)
As a result of early experience with
professional tube-based video cameras, many producers concluded that
film had a major advantage over video. However, when the latest
generation of professional CCD cameras are manually setup (as opposed
to relying on automatic settings) brightness range capabilities end
up being similar to film.
In addition to
brightness range there is also the issue of tonal rendition, or how
different tones and colors will be reproduced. This can also be made
to match film. Specifically, the tonal range of video at the top of
the white range and in the shadow areas is expanded through the use
of a dynamic contrast circuit. When properly set up these circuits can
handle video in excess of 600% over peak white without loss of picture
detail, while still retaining detail in dark shadow areas.
In fact, if the "film look'' is
important, there are camera adjustments and postproduction approaches
that can make broadcast video indistinguishable from film.
Thus, the old arguments about video's
limited brightness are, at best, questionable—at least with the latest
generation of professional CCD cameras. (In demanding still photography
applications many photographers are finding that they can do a better
job of retaining difficult
tonal ranges with CCD-based still cameras than they can with film.)
Single-Camera, Multiple-Camera
Production Differences
Purely
technical considerations aside, the primary underlying difference between
film and video lies in the way it's shot.
Film is normally shot in a single-camera
style, and video is normally shot using a multiple-camera production
approach.
In film each scene can be carefully set
up, staged, lit, rehearsed, and shot. Generally, a number of takes are
made of each scene and the best one is edited into the final production.
As they strive for perfection in today's high-budget feature film productions,
some directors re-shoot scenes many times before they are satisfied.
(Possibly the record is held by one well-known film director who
reportedly shot the same scene 87 times.)
Quite in contrast, video is generally
shot with several cameras covering several angles simultaneously. Instead
of lighting being optimized for one camera angle, it must hold up for
three or more camera angles at the same time. This means that
it is generally lit in a rather flat manner, which sacrifices dimension
and form. And, with the exception of single-camera production,
multiple takes in video are the exception rather than the rule.
Film and Videotape Costs
The
minute-for-minute cost of 16mm and 35mm film and processing is hundreds
of times more than the cost of broadcast-quality video recording.
And, unlike film, tape is reusable, which
results in even greater savings. But, this can also be a mixed blessing.
The tendency to reuse videotape means
that the record of many events is lost when the tape is reused. This
sometimes presents problems when attempts are made to do historical
documentaries.
Offsetting the savings with video is
the initial cost of video equipment. Depending on levels of sophistication,
the initial investment in video production and postproduction equipment
can easily be ten times the cost of film equipment. The cost of maintaining
professional video equipment is also greater.
On
the other hand, as we've noted, there is a substantial cost savings
in using video for postproduction (special effects, editing, etc.).
For these and other reasons film productions intended for television
are routinely transferred to videotape. This
transfer can take place as soon as the film comes out of the film processor.
Reversal of the negative film to a positive
image, complete with needed color correction, can be done electronically
as the film is being transferred to videotape. From this point on all
editing and special effects are done by the video process. The negative
film is then locked away in a film vault and kept in perfect condition.
Even for film productions intended for
theatrical release, major time and cost savings can be realized by transferring
the film to videotape for editing. Once edited, the videotape is then
used as a "blueprint'' for editing the film.
Studio
Production Standards
So-called
digital cinema or
e-cinematography
(electronic cinematography)
is rapidly gaining ground, especially since it is becoming almost impossible
to distinguish between the two when they are projected.
Digital cinema seems to be moving toward
two HDTV standards: 24p (24-frame progressive) and 60i (60-field interlaced).
The Sony camera on the left is capable of either of these standards.
Those who are after the "film look"
prefer 24p, especially since the progressive approach results in fewer
artifacts (aberrations) and higher resolution. The 24 fps speed
is also the same as film—even though the extra sharpness of video
sets it apart from film. (That extra sharpness has been termed "too
real" by film purists.)
However, compared to 24p, 60i (30 fps)
seems to do a better job of tracking motion, which means that zooms
and camera movements—especially when done quickly—appear smoother.
Either of these standards can be converted
to film.
At the same time we are seeing the beginning
of a move to digital
projection, or movie theaters
that use video projection equipment. Distributing digitized copies
of films to theaters by satellite represents numerous advantages.
Will Video
Replace Film?
So
will video soon replace film for prime-time TV production?
Yes, eventually, just as it will eventually
replace film in motion picture work. The move is well underway, as evidenced
at the 2000 Sundance Film Festival.
But right now "Hollywood" has
a tremendous investment in film technology. Plus, top creative personnel
typically come from a film background.
But, as we've noted, things are changing,
driven primarily by new technology and bottom-line economics.
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