TVB Staff /
11.25.2008 08:50 AM
Q&A: Mark Schubin Will Talk Optical Issues at GV Expo
contributor and multiple Emmy-Award-winning SMPTE Fellow Mark Schubin will discuss the optical issues of shooting video next month at the 11th annual Government Video Technology Expo.
During his session, “The Format Factor,” Schubin will highlight lens-iris settings, focal length, depth-of-field and image sharpness.
GV Expo runs Dec. 2-4 at the Walter E. Washington Convention Center in Washington, DC. “The Format Factor” is part of this year’s Government Video Conference Program. Admission to the show floor is free for all registered attendees, but there is a charge to attend the Government Video Conference Program.
Schubin has been working professionally in the television industry since 1967, with clients ranging from the World Book Encyclopedia to government agencies. He has been involved in many famous video projects, from Sesame Street to Japan’s first HDTV broadcast, and has written a monthly column in TVB
sister publication Videography
for more than 32 years.
He gave Government Video
editor, Dr. Mark Pescatore, a sample of what to expect:
How do differences in image sensor size affect the image?
“With all else being equal, a larger image sensor offers less depth-of-field, more sensitivity and dynamic range, and sharper images. But there’s also an interaction with iris settings. Few people realize that f
-stop can actually affect picture resolution, thanks to diffraction effects.
Then there are contrast issues. I’ll actually demonstrate how two people looking at the same face on the same screen can see two very different characters based on the human contrast-sensitivity function. It’s pretty amazing and worth learning.
What are some major changes that SD shooters need to be prepared for when they switch to HD?
“HD requires more--more storage capacity, more bits per second, more attention to make-up and lenses, and so on. In shooting SD, it’s safe to ignore diffraction, but in HD you can’t.
What is your biggest HD pet peeve, the misconception that drives you crazy?
“My biggest peeve is that the words ‘high definition’ have some specific meaning. A report to the British Parliament in 1935 recommended that only HDTV be broadcast; they defined it back then as having no fewer than 240 scanning lines.
The most expensive HD camera today costs in the range of a quarter-million dollars; the least expensive is just over $100. That’s a range of about 2,000:1. Do you really think they’ll offer the same quality pictures?
As for ‘high-definition light’ and ‘high-definition camera mounts,’ don’t get me started!”
More information on the Government Video Technology Expo is available at www.gvexpo.com