In another article, I made the point that 8 megapixels is probably more than enough for most people’s needs. But that’s a moot point, since most midrange and even consumer grade cameras now come with 10 MP. And within a couple years, the minimum will probably be 12MP. In short, almost every SLR released by Nikon or Canon today (and in the future) has enough megapixels.

And that’s for advanced enthusiasts and professionals. What about regular consumers using consumer model SLRs and even point-and-shoots? Most digital point-and-shoot owners print at 4x6, and occasionally at 8X10, and they use retail printing services that print at 150 dpi resolution. Yet an 8X10 print at 150dpi only requires a 3.2 megapixel camera. A 5 MP camera would do more than meet their needs.

Yet many point-and-shooters are buying cameras with 8MP, 10MP, or even greater resolution. This excessive focus on megapixels is probably doing more harm than good for consumers, costing them both money and image quality. Here’s Janice Chen at ZDNet:

…almost 80 percent of digital cameras sold in the U.S. in August 2008 were 8-megapixel or higher resolution models, with a whopping 27 percent of them 10 megapixels and more. If that doesn’t sound surprising, compare it to the numbers from a year ago when only 20 percent of cameras sold in August 2007 had 8 megapixels or more (according to NPD Group Inc. and the PMA Monthly Printing and Camera Trends Report).

While she couldn’t give me more recent numbers, a PMA spokesperson informed me that digital SLRs accounted for only 10.3 percent of digital cameras sold in 2007 (9.5 percent in 2006), which means that many of the aforementioned megapixels are probably being wasted on compact or low-end cameras like this one whose limiting factors are not resolution but small sensors and/or lower-quality lenses. Because the average consumer still doesn’t understand that higher resolution doesn’t equal better pictures, camera manufacturers continue to jack up the megapixels even if it affects image quality negatively–which too many megapixels in a compact camera arguably does by introducing more noise while cramming more pixels onto smaller sensors.

 

Comparing Prints: Can You Tell the Difference in Camera Resolution?

We can take this a step further. There’s increasing evidence that vast majority of people can’t tell the difference between 5MP and 12MP prints, EVEN AT LARGE SIZES of 11X14 or larger.

David Pogue recently enlisted the help of Ellis Vener, Technology Editor at Professional Photographer magazine, to conduct and experiment. After readers rejected to an earlier experiment, he asked for help devising “a test that would isolate megapixels as the sole difference between the test photos -- without involving Photoshop.” Vener suggested a precise method.

Using a professional camera (the 16.7-megapixel Canon EOS-1Ds Mark II) in his studio, he would take three photos of the same subject, zooming out each time. Then, by cropping out the background until the subject filled the same amount of the frame in each shot, he would wind up with nearly identical photos at three different resolutions: 7 megapixels, 10 and 16.7.

His choice of subject also put to rest another objection to my original test. Instead of a smooth-skinned baby, Mr. Vener's model was positively bristling with detail: curly hair, textured clothing, a vividly patterned background and a spectacular multicolored tattoo on a hairy arm.

We set up the new 16-by-24-inch enlargements on identical easels at a public library. (Why the library? Because it was warm, it was flooded with natural light and its director gave me permission.) Clipboard in hand, we conducted the test again.

Surprise, surprise: the results were the same. This time, out of about 50 test subjects, only three could say which photo was which.

…But you can repeat this lesson until you're blue in the newspaper column, and some people still won't believe you. They still worry that their 5-megapixel camera from 2005 is obsolete. They still feel sales pressure when shopping for new cameras.

This is not the only experiment to indicate that viewers have can’t tell the difference between high and low resolution images.

Here’s Thom Hogan’s take: www.bythom.com/printsizes.htm

…once we get to 8mp we essentially get good results at everything a desktop inkjet printer is capable of printing (up to 13x19").

…if you set up a shoot correctly (exposure, camera settings, shot discipline, etc.), use the base or next ISO value of the camera, manage the post processing correctly, do only modest up-sizing (if any), and pick the right options from your printer driver, then you should be able to get that good or excellent print out of virtually any of the currently available DSLRs on the market at up to the maximum size the desktop inkjets can produce. Many of us manage to do better than that. I've produced and seen 36" prints from a 12mp camera that look excellent, though it takes a great deal more control over every variable from shoot-to-print to do that with any consistency.

Here’s Ken Rockwell (although he’s admittedly controversial on this issue):

For normal 4x6" (10x15cm) prints, even VGA (640 x 480 or 0.3MP) resolution is just fine. Digital cameras did this back in 1991!

In 1999 when digital cameras were only 1.2 or 2 MP, each megapixel mattered if you were making bigger prints.

Today, even the cheapest cameras have at least 5 or 6 MP, which enough for any size print. How? Simple: when you print three-feet (1m) wide, you stand further back. Print a billboard, and you stand 100 feet back. 6MP is plenty.

Sharpness depends more on your photographic skill than the number of megapixels, because most people's sloppy technique or subject motion blurs the image more than the width of a microscopic pixel.
Even when megapixels mattered, there was little visible difference between cameras with seemingly different ratings. For instance, a 3 MP camera pretty much looks the same as a 6 MP camera, even when blown up to 12 x 18" (30x50cm)! I know because I've done this. Have you? NY Times tech writer David Pogue did this here and here and saw the same thing — nothing!

Joe Holmes' limited-edition 13 x 19" prints of his American Museum of Natural History series sell at Manhattan's Jen Bekman Gallery for $650 each. They're made on a 6MP D70.

What’s the moral of all this? Friends don’t let friends fixate on megapixels. When you’re shopping, or giving advice to others, focus on attributes other megapixel count.