The Datavideo VS-100 video scope is a
very compact, portable video signal-testing
device used for calibrating
cameras and synchronizing the calibration
of multiple cameras on any location. It provides
four, fully professional analysis tools:
vectorscope, waveform monitor, histogram,
and parade display.
The Datavideo VS-100 is small enough to
fit in your back pocket, but contains a full
set of vital video signal testing tools that any
serious videographer needs to ensure that
the cameras he or she is using perform to industry
standards. One can use the VS-100 to
run a series of tests on a single camera to assure
it’s up to specifications; but the device
becomes even more essential when one is
shooting with multiple cameras. In this case,
all cameras can be calibrated to the same
performance level to ensure that they produce
footage that edits together seamlessly,
with no color or luminance shifts, thus saving
hours of correction time in post.
The Datavideo VS-100 accepts an SD or
HD-SDI input from any video camera for
analysis. The graphic output can be monitored
on any display unit with an HDMI or
HD-SDI connection. The VS-100 also has an
SD/HD-SDI loopthrough, which provides a
clean signal for alternative monitoring options,
or to pass video on to an external recording
tests and calibration,
live action by selecting
the Video Display
option on the menu,
and—because the VS-100 converts
an SDI signal to HDMI—it
provides HDMI monitoring from cameras
that only have an SDI/HD-SDI output.
The VS-100 supports the most commonly
used SDI/HD-SDI video formats: NTSC and
PAL SD (interlaced or progressive), and
1080i or 720p at 50 or 60 Hz.
The VS-100 is about 3 x 4 x 1-inches and
weighs about nine ounces. It’s powered by a
simple 12V DC converter.
I connected the VS-100 to a Panasonic
AG-HPX170 HD video camera via the HDSDI
output and then connected the VS-100
to a standard HDMI monitor.
Using the VS-100 is about as simple as it
gets. I turned it on and immediately saw the
first test screen and menu options displayed
full-screen on the HDMI monitor. I then
switched on the camera. The first screen I
viewed was the waveform monitor function.
The display was large and detailed, graphically
displaying the light levels throughout the
frame. There’s also a thumbnail image of the
actual video on the lower left corner, which
helps to interpret the light and dark portions
seen in the waveform display. There’s also an
audio level monitor that displays up to eight
tracks. An audio signal for aural monitoring is
provided via a headphone jack.
Pressing on the menu item called “Next
Mode” scrolls you through the different test
tools. With a push of the button, I first called
up the histogram function that displays the
light levels in vertical bars across the screen;
then I accessed the vectorscope display,
which graphically displays the color elements
in the scene. Finally, I tried out the parade
function, which displays the basic RGB
color components in three vertical columns.
The VS-100 allows you to zoom in to examine
fine detail in the waveform/vectorscope
modes, allowing you to concentrate on small areas of the frame and make lighting
adjustments before shooting, thus cutting
hours of time trying to correct in post.
I’m not a video engineer, and one of my
delights in using the VS-100 was finding that
I didn’t have to be to use the instrument
correctly. The instruction manual provides
very clear and simple instructions that allow
anyone to accurately evaluate video signals.
Once any imbalances are found, of course,
one has to know how to manipulate the
camera functions to make the corrections.
However, the VS-100 does all it can to lead
you in the right direction.
I walked through the step-by-step set of
instructions and found it much easier to
navigate than I had expected.
The instruction manual includes a series
of six tests screens that allow users to accurately
calibrate a single camera, and, if necessary,
match multiple cameras for identical
signals. The VS-100 employs an ingenious
way of accomplishing this. Once you tweak
the first camera to match ideal specs as
closely as possible, you create a trace of the
displayed pattern, which is remembered by
the VS-100. Then as you calibrate subsequent
cameras, you adjust them to match the same
graphic patterns produced by the first camera.
It’s really a brilliant solution.
I worked through all of the tests in about
15 minutes. Many are very simple to perform.
For example, testing the white and
black balance only requires you to point
the camera at a white card and tweak the
adjustments until the white dots all sit in the
center square of the vectorscope display.
Luminance adjustment is done with similar
ease using the histogram, or the waveform
monitor displays using a grey-scale card.
Color and hue adjustments can be tricky,
but again, the VS-100 makes these very
straightforward. Using the parade screen,
I pointed the camera at a color reference
chart and saved the trace of the pattern.
Then, if it’s necessary to match another camera,
I could recall that saved trace and tweak
the other cameras to conform to the parade
pattern produced by the first.
With the VS-100, you can even check for
the basic performance and signal quality of
cameras. For example, I found that I could
connect different cameras, turn them on
with the lens capped, and then gauge the
amount of inherent noise produced by looking
at the width of the white bars on the bottom
of the parade screen.
Overall, I found the VS-100 refreshingly
easy to use and incredibly useful for tweaking
cameras to provide the best possible images.
The only limitation lies in the available
image adjustment controls in the camera. In
general, less expensive cameras do not offer
the same ability to easily change characteristics
(hue, saturation, gamma and the like).
However, the VS-100 is ideal for a professional
videographer who needs to achieve the
best camera match with multiple cameras.
I tested the VS-100 with the idea of
matching several freestanding cameras in a
multicamera shoot. But there’s also another
ideal application for it—a multicamera
shoot, with CCUs and the cameras connected
through a switcher, such as one would
find in a television studio. In this case, all of
the camera adjustments can be made via the
individual CCUs instead of tweaks inside
the cameras. The VS-100 would be used the
same way, but calibration would be easier, as
it’s all done through CCU controls.
The Datavideo VS-100 is a remarkably
useful, portable and inexpensive solution
for calibrating multiple cameras in the field
or studio. Its step-by-step instructions allow
you to accurately match the key image attributes
of cameras that are being switched
live, or used in independent shooting. An
added bonus is that the device provides a
means of connecting any HDMI monitor to
a camera with only an SDI output. However,
its most attractive attributes are its versatility,
sophisticated engineering, and ease of use.
Geoff Poister, Ph.D., is a member of the
Film and Television faculty at Boston University
and a regular contributor to TV
Video evaluation and camera setup
Small form factor, lightweight,
multiple displays, storage and