The Datavideo S-100
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 device.
Once you’ve completed tests and calibration, you can monitor 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 Technology.
Video evaluation and camera setup
Small form factor, lightweight, multiple displays, storage and recall capability