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Videography Basics
In video, dynamic range is often discussed in reference to the luminance or bright-
ness of the video signal. DV works on a digital scale of values from 16 to 239 for
brightness. That's the total allowable or viewable range of values that can repre-
sent how bright or dark a pixel is.
Why is dynamic range important? Well, the more of your dynamic range you use,
the more full and realistic your audio and video will feel. Hearing a symphony
play on a well-recorded CD can have much more impact than listening to the
same recording on an AM radio. Why? Because there is much more dynamic
range possible on a CD than an AM radio.
With video, it's tougher to talk about examples. The popular Lord of the Rings
DVD has some excellent examples in its Bonus Materials. The cast interviews on
the set look great. They are very well defined and more “crisp” than many other
video shots. When comparing such great looking shots to much of the footage
shot on DV cameras, it's easy to say things like “Well, that was shot on a better
camera.” Is that really why it is better? Or is it simply better use of dynamic
range? The interviews were lit to take full advantage of the video palette. The
shadows are more defined, the whites of the eyes are bright white, but not too
white, etc.
The biggest difference between a high-end DV camcorder and a prosumer DV
camcorder is not dynamic range, both record to the same tape format. It's how
well the high-end camera fills the available dynamic range with useful informa-
tion. In many cases, a prosumer camera can achieve the same results as a high-end
camera if you set up your shot efficiently using objective monitoring tools. Seeing
how the camera is using the dynamic range of brightness, for example, can keep a
shot looking “crisp” instead of washed out. This is one of the big advantages of
DV Rack. Tools like the Waveform Monitor, Spectra 60 and SureShot let you maxi-
mize your signal to fill the available dynamic range. This can only be done at the
time you are shooting because the expanded dynamic range must be captured on
location by adjusting your camera, lights and scene composition. Attempting to
do this with editing software after the fact would be like trying to expand a one
megapixel digital still to four megapixels in a paint program. You just can't put
back information that wasn't captured in the first place.
Another benefit to using as much dynamic range as possible is that in post-pro-
duction more dynamic range means more latitude in applying image processing.
If, for example, you shoot an intentionally dark shot that uses only the lower 60%
of the brightness range available to you, it will be difficult to brighten or expand
this range while editing. You'll likely introduce banding artifacts because you're
attempting to expand a limited brightness range. It is preferable to use 100% of
the dynamic range available to you when shooting and then darkening it in post-
production to the lower 80% instead of shooting at 60% and trying to expand to
80%.
