The myth of maximum megapixels

Megapixels matter less than you'd think

Camera vendors and consumer electronics retailers sell digital cameras as if the pixel count -- the number of pixels a camera's electronics can capture -- is the most important measure of quality. I'm here to tell you that pixel count has become unimportant almost to the point of irrelevance. Megapixels don't matter anymore.

Ten years ago, consumer-level digital cameras weren't capable of taking good pictures. The optics were lousy, the electronics were unsophisticated, and the settings were relatively limited. Buying a better camera back then meant spending big bucks for a 2-megapixel model rather than, say, a 1.3-megapixel one.

As overall digital camera quality rose, so did pixel counts. Then, a couple of years ago, the industry silently passed an invisible milestone: Affordable consumer cameras reached, then exceeded, the number of pixels nonprofessional photographers could practically use. The current standard is just over 10 megapixels.

In an effort to convince you that your camera is obsolete and you need to buy a new one, camera vendors keep harping on the more-megapixels-are-better myth.

Their message isn't completely false. In fact, older cameras are obsolete, and if you own one, you do need a new one -- but not necessarily one with maximum megapixels.

The reality is that all areas of digital camera technology were improving at about the same rate as pixel counts were increasing. Most of these advancements have resulted in better photos for amateurs; picture quality is way up, and so are pixel counts. Vendors will tell you that these two facts are linked. But what they don't tell you is that the improvement in picture quality is the result of improvements in just about every aspect of a digital camera except pixel counts.

The reality is that these other factors, which make or break digital camera image quality, are complex. Most buyers aren't willing to put in the time it takes to understand those factors, so everyone clings to a simple metric -- pixel count -- that appears to correlate with quality.

Each amateur photographer has a pixel count "sweet spot" that best suits his photography style and abilities. For most people, that's somewhere in the 4-to-6-megapixel range. Above that, however, increasing the number of pixels generally reduces the quality of pictures.

That's right. I said it. More megapixels are bad. Here's why:

Megapixels are expensive. Assuming you have a set budget for buying a new camera, the quality of pictures generally will be better if you spend less on pixel count and more on image sensor quality, lens quality, better electronics and faster performance. I'll discuss these factors a bit later.

Megapixels are slow. Higher pixel counts means more data flying around in your camera's electronics. It takes longer to move more data than it does to move less. In general, cameras with higher pixel counts are slower to start, and they write files to disk more slowly than similarly priced cameras with lower pixel counts. All those pixels won't matter if you miss the perfect shot altogether because you're waiting for your camera.

Megapixels are big. Higher pixel counts can generate JPEG images that are several megabytes in size. In addition to slowing things down, these larger files will eat up on-camera storage space quickly. The larger files can also eat up hard disk space on your PC over time. In general, larger file sizes can motivate you to take fewer shots, which reduces your chances of capturing better pictures.

Don't get me wrong: High-pixel-count cameras aren't bad for everyone. Professional photographers and advanced amateurs have the skills and knowledge to intelligently buy and use these cameras. Even for amateurs, higher pixel counts admittedly give you more flexibility in cropping, which can improve quality.

However, the reason I argue against maximum megapixels is that other factors, not a lack of pixels, are much more likely to wreck your pictures. Here are a few things that can cause bad pictures:

Bad lighting. One common mistake is to habitually use a flash when it's dark. This gives people captured in pictures that deer-in-the-headlights look and makes the background vanish into darkness. A related mistake is to never use the flash in bright sunshine, which results in dark shadows that can ruin the shot.

A good digital camera will feature options and presets that fix lighting errors. Night shots, for example, are often improved by presets that both use the flash and provide a long exposure, which illuminates both subject and background. And you should be able to very quickly force the flash to operate in bright light while still using the automated settings.

A related quality to look for when buying a camera is image sensor "sensitivity." The difference between a camera that maxes out at ISO 400 and one that goes up to ISO 1600 is the difference between night and day -- literally. At higher ISO settings, you can take pictures of darker scenes without any flash at all, which provides a more natural, more evenly illuminated shot.

The speed at which you can set these lighting options can mean the difference between capturing a great shot or missing it.

Bad timing. By definition, photographs capture an instant in time. Say something amazing, funny or unusual happens right in front of you. How long does it take to turn on your camera and take a picture of it? How long to auto-focus? How long to take the second and third picture? And what will you miss while you're waiting for your camera?

If your digital camera is slow -- as most of them are -- you could miss the best shot.

Have you ever seen professional photographers work? They usually take an enormous number of pictures quickly. The reason is obvious: Taking more pictures increases your chances of capturing just the right moment.

The single best thing about digital cameras is that they let us amateurs do that, too. We can take a hundred pictures instead of one, and all those extra pictures are free!

You'll be a much better photographer if you spend your money not on megapixels, but on the fastest possible boot-up time and auto-focus -- and minimum shutter lag (the amount of time between button press and shutter opening).

Even better, look for a camera that captures the maximum number of pictures in rapid sequence, and use this setting regularly. Pick the best shot of the bunch and toss the rest. People will wonder how you became such a great photographer.

Bad optics. Image sensors can capture only what the lenses allow through. High-quality, well-positioned and -sized lenses are the foundation of great photography. Digital cameras are electronic, and we get caught up in the speeds and feeds. But all the digital processing in the world can't fix images ruined by low-quality optics.

You can get better pictures out of a 3-megapixel camera with superior optics than a 12-megapixel camera with a mediocre lens, everything else being equal. Also, watch out for digital zoom, which is a marketing gimmick that preys on the ignorance of the buyer and is useless for taking pictures. The first thing you should do after buying a camera is to disable digital zoom. Digital zoom is nothing. Optical zoom is everything.)

Note that these are serious issues and that adding more megapixels won't fix any of them. By spending less on pixels counts and more on lighting, optics and speed, you will end up with much better pictures. Trust your own eyeballs, not pixel counts, when buying a camera.

Also, visit the sites listed at the end of this article. They'll tell you everything you need to know about the quality of each camera. More important, they'll show you actual photos taken with each camera, so you can choose a camera based on picture quality.

The conventional wisdom is that professionals need super-high-quality cameras, while consumers, who buy cameras to take casual snapshots of their kids, need only mediocre models. I think that's all wrong. What's more important to you: a picture of some random model hawking overpriced jewelry in a glossy magazine, or capturing your child's first steps?

Buy a great camera, but be smart about it. Spend your money on maximum picture quality, and just say no to maximum megapixels.

Mike Elgan is a technology writer and former editor of Windows Magazine. He can be reached at mike.elgan+computerworld@gmail.com or his blog: http://therawfeed.com

Related links:

Digital Photography Review

Steve's DigiCams

Photography Review

Imaging Resource

Megapixel.Net

Related Computerworld blogs:

Copyright © 2006 IDG Communications, Inc.

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