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Monday, February 1, 2010

With film, the output of the video- assist tap was never considered to be more than a way of seeing composition and performance, and maybe a way of double-checking that there weren’t any booms in a shot. But that was okay. Everyone was used to it. They trusted the DP and believed that the exposure would be correct for the film stock being used, that the lab would process the film correctly and that some time in color grading would produce the required footage.

Fast-forward to using digital capture. First, you’re not sharing light. You’re looking at images derived directly from the image sensor. The image is bright and more realistic. If you take the time and spend the money, you even can bring on-set monitoring that allows LUTs to more accurately show you the look that you might approach in grading.

But, many times, the output of the camera is still fed to run-of-the-mill video-assist monitors. Why? Besides budget, the mind-set may be similar to a film mind-set. The workflow isn’t changing, so grading will be done later. In other words, just look at the monitor for composition, performance and the boom. Nothing to argue with there if you don’t have the type of monitoring setup to try to do more.

There’s one big problem, however: The picture looks good. Not great, but compared to a video-assist tap on a film camera, it looks really good. And the conversations of those looking at the picture are becoming peppered with references to image quality, like it or not. Sure, you can tell everyone to remember they’re not looking at the finished product, but sometimes people just don’t listen.

By now, you probably wonder what this has to do with test signals. In the scenario I mentioned above, remember all the monitors on set? It would be great if all of the monitors displayed a similar image. Yes, they all have different performance characteristics, but you can get them close.

I arrived on this set with a portable test-signal generator. In this particular case, I was testing an Ensemble Designs BrightEye 57. It’s portable and programmable. It can output HD-SDI for the set monitor, SDI for the on-set edit system and analog for one of the client monitors. It outputs several different test signals with a press of a button or click of a mouse.

Yes, I could have had the AC pump out bars from the camera, but the various paths the signal went through made things a bit complicated. Being able to use a test-signal generator allowed me to get the monitors set up quickly and properly. A grayscale ramp showed me how the monitors’ brightness and contrast were set, and color bars let me check color.

I was able to bring the generator to each monitor for initial setup and then test the whole cabling system. Since I knew that the monitors were set up properly, any differences once they were cabled could be attributed to other problems. Everything is digital, so no problem, right? In this case, however, the method of recording into the edit station was via a video deck. The input level on the deck was about 15% down. True, this was just an assist recording, but getting it right avoided a lot of questions.

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