Director of Photography
This question was recently posted on the Cinematography Mailing List:
“I need to match two Sony EX3 cameras to an HVX-200. How do I do it?”
My suggestion was to shoot a perfectly lit and exposed DSC chart on all three cameras, using the same criteria for setting exposure (placing the white chip on the chart on the same luminance value for all three cameras) in order to facilitate post color matching. A colorist should be able to match the cameras by looking at the star pattern the chart creates on a vectorscope and bending the points of each camera’s star to match. It’s important to match the cameras’ gamma and knee settings in advance, as a colorist may have a more difficult time matching those. The DSC chart’s gray chips form an “X” pattern on a waveform monitor, and the goal is to create matching “X” patterns on all three cameras. Match the most adjustable camera (the EX3) to the least adjustable camera (the HVX-200) by manipulating the gamma and knee settings. The knee circuit will interfere with the top part of the “X” pattern so it’s probably best to shut that off and adjust it separately after gamma matching is complete.
If you have some time to spend in prep it might be possible to match camera colorimetry in advance using the EX3 user matrix. Using the less adjustable HVX-200 as a reference, adjust the user matrix for each EX3 so that the star pattern, created by the DSC chart on the vectorscope, matches that of the HVX-200. Always use a single waveform/vectorscope and monitor when matching cameras. No two monitors are the same, so looking at all three cameras through a single monitor eliminates that variable. Route the HVX-200 into the “A” input on the waveform/vectorscope and one of the EX3’s into the “B” input, and then toggle between them while making adjustments. Once the first EX3 is matched to the HVX-200, repeat the process with the second. The Leader 5750 waveform/vectorscope is a great tool for this as it is simple to capture a still frame from one camera’s star or “X” pattern and overlay a live image from the other camera on top of it. Then it’s just a matter of adjusting the second camera’s pattern so that it overlays the first.
One local rental house took this a step further and matched their EX3’s colorimetry to a Varicam, as they considered the Varicam’s colorimetry to be more pleasant.