4K TVs were all the buzz at this year’s CES (second only to earbuds in prominence), a fact that led to a good amount of head-scratching between me and my journalist friends at the show. Which, of course, led to a number of geeky conversations over cocktails, and one or two seriously mathematically-charged phone calls afterward between me and my friend Geoff.
We both came to two solid conclusions: 1) 4K TVs make next to no sense, and 2) we were both going to write articles about why 4K TVs make next to no sense. Geoff beat me to the punch, though, and quite frankly, his article is so thorough and spot on that I really don’t feel like I have anything further to add. You should read the whole thing, for sure (especially if you plan on arguing with him), but here are a few of my favorite bits:
With the huge screens of most modern movie theaters, and the move toward digital projection, 4K makes a lot of sense. The prevalent 2K (2,048×1,080 pixels) digital cinema projectors are only slightly higher resolution than 1080p. I’ve seen a lot of these, and I can often see the pixel structure from most of the seats. You definitely don’t with 4K, which is why it’s a brilliant idea for movie theaters.
But 4K in the home is stupid. Here’s why.
Depending on technology, a 1080p 50-inch flat panel TV’s pixels are approximately 0.023 inch wide. This is presuming they’re square (many aren’t) and that there’s no intra-pixel distance (there is). The plasma I photographed for the lead image above measured 3 pixels per 1/16 inch, which is 0.021 inch per pixel. So we’re in the ballpark.
Most people sit about 10 feet from their television. At 10 feet (120 inches), your eye can resolve an object 0.035 inch wide, if like I said above, there’s enough difference between it and the background (or its adjacent pixel, in this case).
What’s interesting is that a 720p, 50-inch TV has pixels roughly 0.034 inch wide. As in, at a distance of 10 feet, even 720p TVs have pixels too small for your eye to see.
That’s right, at 10 feet, your eye can’t resolve the difference between otherwise identical 1080p and 720p televisions. Extrapolating this out, you’d have to get a TV at least 77 inches diagonal before you’d start having a pixel visibility problem with 1080p.
So if your eye can’t tell the difference between 720p and 1080p on nearly all modern televisions, what’s the need for 4K?
Head over to Geoff’s CNET blog to read the entire article, because there’s some great stuff (including math!) that I’m leaving out.