As this is written, it's estimated that there are some 15 million households worldwide that "receive and watch HD programming," some 91% in the U.S. and Japan. I wonder how many of them actually can see the HD because the screens they bought are placed too far from their viewing position. The visual acuity of the human eye with 20/20 vision can detect and resolve details as small as 1/60th of a degree of arc. Beyond a certain distance, the contributions of individual pixels blend together as do faces in a crowd or blades of grass in a lawn and the original resolution is lost.
It's possible to calculate what this means for the individual pixels on an HD screen and there are several rules of thumb (three times the screen height or double the screen diagonal distance) available online by doing a search on "hdtv screen size." Collins' Cinema My Home Theater site has a viewing distance calculater that's very handy in judging how big an HD screen to buy or how close to sit to your screen to get the HD benefits.
You'll think the latter is too close for comfort.
Here in my household, we have two small wide-screen monitors capable of displaying HD. DirecTV and DVD are the primary program sources but the bedroom one also has a USDTV ATSC converter box capable of HDTV output. In the livingroom (which for years had no TV at all), there is a 26-inch (66-cm) diagonal LCD monitor placed 12 feet (3.7-m) from the couch. For HDTV, the viewing distance calculator says that we should sit no more than 3.4 feet (1-m) for our eyes (with our glasses on) to detect HD. In fact, it would take a 92-inch (2.3-m) diagonal screen to fully resolve HD at 12 feet. The TV in the bedroom is a 30-inch (76-cm) diagonal CRT monitor placed 10.5 feet (3.2-m) from the viewing position. This gives me a generous 3.9 feet (1.2-m) to fully view HD -- that is, with the monitor sitting on my knees when I'm laying in bed.
No wonder when broadcast engineers check out HD monitors, they all but get nose prints on the screen.
I've been lusting after the new HD-DVD or Blu-ray DVD players, but we won't be buying one of those any time soon. I paid under $1,000 for each of the HD monitors in my home, so it's not a big deal, but at the viewing distances we have, we would have had the same results with less expensive EDTV monitors.
Still the most popular single article ever posted on this weblog was "How To Buy A TV" by Twin Cities Public Television's chief technologist, Bruce Jacobs, from just over two years back. It's worth rereading if you're in the market for monitors or DVD's today, and also worth considering if, as we are at the TV stations I manage, you're in the market for HDTV production gear. --Dennis