High-def viewing isn't always clear

Q Last week my husband and I went shopping for a TV. We decided on a 50-inch plasma model and compared the 720p version with the 1080p version. The salesman went on and on about "1080p Full HD," while I couldn't see a difference between them at all! I don't understand the big deal, and the 1080p model was $500 more than the 720p model. Why would I want to spend $500 more, when I can't see a difference when the TVs are right next to each other?

LISA KNIGHT, BETHEL PARK, PA.

A I commend you for seeing through the sales pitch and making your own decision about picture quality. You got it right. If you are looking at televisions 56 inches or larger, I would lean toward 1080p, but on smaller sets, 720p will be fine.

On a 50-inch set at normal viewing distances, most viewers are unable to discern the difference between good 720p and 1080p sets. In many real-life situations, it is impossible for viewers to tell the difference between 720p and 1080p.

For example, many consumers buy 42-inch TVs and watch them from 10 feet away. At that distance, the human eye cannot discern all of the information in a 720p picture, let alone a 1080p picture. You can learn more about 720p vs. 1080p, screen size and viewing distance by reading Geoffrey Morrison's excellent article at www.startribune.com/a4449.

When shopping, you might see differences between makes and models of televisions or if one TV has its picture settings set more accurately than the other. But the 1080p phenomenon is often much more marketing than substance.

The "Full HD" and "True HD" terms are nothing more than marketing slang, because 720p and 1080i also qualify as full, true high definition.

There is one situation where you might see a difference between smaller-sized 720p and 1080p models, but it is unrelated to the resolution of the set.

Blu-ray Disc movies are almost always recorded in 1080p resolution at 24 frames per second, referred to as 1080p/24. If you get a TV with a 1080p/24 compatible input and your Blu-ray player has a 1080p/24 output, using the 24fps settings might render a more filmlike image. It won't be a difference in resolution but in motion, because viewing at the original 24 frames per second often leads to a smoother, more filmlike look.

Although you might see a slight difference, the operative words are "might" and "slight."

When you get that beautiful big new TV home and feed it a high-definition signal from cable, satellite or Blu-ray, you are likely to just sit back and smile at the beautiful image, not nitpick numbers such as 720p, 1080p and 24fps.