Tech writer David Pogue has a new Discovery Channel show coming out titled It’s All Geek to Me which I’m going to have to make a point of watching, but in the meantime I’ll just keep reading his articles in the NYT. One of the shows he just finished dealt with the topic of digital cameras and he spent part of it wandering into different camera shops posing as someone who didn’t know a lot about digital cameras and seeing what he was told by the sales clerk. One of the things he was told time and again was that he didn’t really need anything with more than 5 megapixels for prints up to a smallish poster size. He says every time he writes something like that in his column he gets tons of emails from people claiming he’s wrong so they decided to put the theory to a test:

On the show, we did a test. We blew up a photograph to 16 x 24 inches at a professional photo lab. One print had 13-megapixel resolution; one had 8; the third had 5. Same exact photo, down-rezzed twice, all three printed at the same poster size. I wanted to hang them all on a wall in Times Square and challenge passersby to see if they could tell the difference.

Even the technician at the photo lab told me that I was crazy, that there’d be a huge difference between 5 megapixels and 13. I’m prepared to give away the punch line of this segment, because hey—the show doesn’t air till February, and you’ll have forgotten all about what you read here today, right?

Anyway, we ran the test for about 45 minutes. Dozens of people stopped to take the test; a little crowd gathered. About 95 percent of the volunteers gave up, announcing that there was no possible way to tell the difference, even when mashing their faces right up against the prints. A handful of them attempted guesses—but were wrong. Only one person correctly ranked the prints in megapixel order, although (a) she was a photography professor, and (b) I believe she just got lucky.

I’m telling you, there was NO DIFFERENCE.

The digital camera we bought a couple of Christmases ago was a 4 megapixel from Canon and it’s been more than adequate for our needs producing beautiful pictures, but then we never go above 8x10 with our prints and 4 megapixels is just about perfect for that size of picture. It doesn’t surprise me then that 5 megapixels is good enough for up to 16x24 pics.

Keep in mind they aren’t saying that the higher megapixel cameras aren’t producing better detailed photos, just that at the sizes most people tend to print their pictures at (8x10 or smaller) the greater amount of data in higher pixel cameras is useless. This is especially true if you’re using the average consumer level photo inkjet printer. If you’re going to blow that picture up to huge proportions or you’re working with professional level printing devices then the more megapixels you have the better the image will be, but for the average consumer using the average equipment right now all you need is at most 5 megapixels.

Just something to consider when you’re shopping for a camera as a Christmas gift this year as there are a lot of good deals out there on 5 megapixel cameras.