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difenbaker
02-10-2007, 03:49 AM
The Truth About Digital Cameras

As loyal Pogue’s Posts readers are no doubt aware, I’ve spent the last seven weeks in TV land, filming a first batch of six episodes of my new Discovery-network series, “It’s All Geek to Me.” It was an exhilarating, exhausting, enlightening journey. Someday when we’re all together, I’ll tell you about it.

Actually, I’ll tell you about one thing right now. We did an episode on digital cameras. Part of the fun involved visiting a couple of big electronics stores, posing as somebody who didn’t know much about cameras, and, later, commenting on what they told me.

The clerks at one store recognized me. The guy at the other store had no clue that I’m a tech writer. Both of them were surprisingly frank, pointing out, for example, that five megapixels is plenty for prints up to smallish poster size.

Now, every time I write that, I hear from furious or baffled readers. “I don’t get it,” wrote one. “A ten-megapixel camera produces photos about 3640 pixels wide–enough to make a 12-inch print at 300 dpi (dots per inch) on a good printer. Sure, you can go lower, but quality is sacrificed; you can’t make an 11×14 print, let alone anything bigger.”

I have to say, the math sounds right. But I also have to say that he’s wrong.

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.

http://img153.imageshack.us/img153/150/21poguespanxj1.th.jpg (http://img153.imageshack.us/my.php?image=21poguespanxj1.jpg)

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.

This post is going to get a lot of people riled up, I know, because in THEORY, you should be able to see a difference. But you can’t.

And I’m hoping this little test can save you some bucks the next time you’re shopping for a camera.

by: David Pogue

from:
http://pogue.blogs.nytimes.com/2006/11/21/21pogues-posts-2/


cheers!

jimbob
02-10-2007, 06:41 AM
I don't see why people would struggle with this concept. Surely it is obvious that the human eye and brain processing are going to be limiting factors in any such subjective test? Nobody thinks it odd that an CRT screen made up of hundreds of consecutively scanned lines doesn't look massively obvious and flickery (the eye and brain deal with it - the image persists a bit and it is all neatly blended by the eye and brain), so why shouldn't similar smooth colour shades placed adjacently at a microscopic level look pretty similar (from 5MP and up on a relatively small print)?

So, for David's and my sake, don't get riled.

P.S. Obviously I accept that as you make the print size bigger, the differences will no longer be at the microscopic level and more megapixels will help, but then, when you have a very big image you often look at it from a distance, so again, it doesn't matter so much...

Michael
02-10-2007, 09:12 AM
Same exact photo, down-rezzed twice, all three printed at the same poster size.What does he mean by down-rezzed? Did he reduce (resample down) the native image size of the 13 and 8 to that of the 5 or something?

difenbaker
02-10-2007, 11:22 AM
From how I understood it, he adjusted the resolution of the image, hence the term "rezzed". One had the equivalent of 13mp, one had the equivalent of 8mp, and the last one - 5mp. All were printed the same size.

Out of all the people who looked at the 3 images... only one got it right, the photography professor. :D

oh and here's a related article:
http://www.kenrockwell.com/tech/mpmyth.htm



cheers!

stephanie
02-10-2007, 10:53 PM
From how I understood it, he adjusted the resolution of the image, hence the term "rezzed". One had the equivalent of 13mp, one had the equivalent of 8mp, and the last one - 5mp. All were printed the same size.

Out of all the people who looked at the 3 images... only one got it right, the photography professor. :D

oh and here's a related article:
http://www.kenrockwell.com/tech/mpmyth.htm

cheers!

I found this on that site too. It's like very interesting.
http://kenrockwell.com/tech/150-vs-5000-dollar-camera.htm#spex

BenXP
02-11-2007, 01:09 AM
I especially liked this article (found through Ken's site): Cameraphone vs. Digital Camera (http://www.16-9.net/lens_tests/k800i/index.html) Interesting and further proves it's more the photographer than the camera which produces a wonderful photograph. :cool: