What are "megapixels"?

Let’s start with the megapixels, which are the basic way to measure how sharp your pictures can be. A Pixel (a word derived from “PIX" (short for "pictures") and "ELement”) is the smallest area of a picture with a distinctive color, kinda like a “molecule” of a picture. If you look real close at a TV or at your monitor (especially if it’s an LCD display), you’ll see there are many tiny squares of color making up the image. Each one of those is a pixel. A megapixel is a million pixels. Your computer screen can probably display one MP or so – in other words, if you display a 4-MP image on your computer, there is some detail you just won’t see. A TV image has between one quarter and one half of a megapixel – it gets fuzzy quite fast if you look at it from very close.

So you can have a real good idea of what it means to have more or fewer pixels, check out these three pictures. The images below have 330 thousand pixels (a third of a megapixel), 80 thousand, and 20 thousand. You can see what a low pixel count looks like, when a low-pixel image is shown way larger than it should be. (But remember, you'll never see pixels that big. Even the third-of-a-megapixel image looks fine, so you can KNOW that no image made by a multi-megapixel modern digital camera will ever look as bad as the second and third pictures below).

330,000 pixels ( 1/3 of a megapixel)

82,000 pixels

20,000 pixels

A high MegaPixel count comes in handy when you want to crop pictures, and when you want to make enlargements. For uncropped 4x6 prints, 2 megapixels are usually enough, but for 5x7s and 8x6s, you kinda need to go up to 3 if you want a sharp picture. If your picture will be looked at from a small distance, I’d suggest a 4MP minimum for pictures that will be enlarged to 8x10. Then again, if your picture will NOT be inspected closely (say it is on a wall behind a couch, so no one will get closer to it than a meter or so away), then 8x6s of 2MP images, or even 8x10s if your 2MP camera has a really sharp lens, should be all right, and 8x10s of 3MP images are also definitely all right if no one comes to within 3 feet or so of them. I have a ton of 8x6s on my wall behind my bed. Most are 2MP, a couple are 4MP, and one is a really sharp 1MP (as far as 1MP images go).

I insist that, unless you're making posters, you don't need more than 3 megapixels, maybe 4. Two-megapixel images make fine 8x6s, and don't let the folks at the store tell you otherwise. Below are a bunch of pictures, all taken with two-megapixel cameras. Do they not look sharp? When you click on these thumbnails to open each file, it might look just a tad grainy, but that's because you're blowing them up to the size of a monitor, about 12 inches on a side, and then looking at them from very close. Besides, your monitor can't show detail as dense and fine as a print could .This means these pictures would make fine 8x12s if you're not scrutinizing the 8x12 prints from like a foot away, or looking at then on your computer. And the 4x6 prints made from these pictures are very, very sharp indeed. I don't think anyone needs much sharper pictures than this, unless you're making calendars, having stuff printed on magazines, or trying to sell your photographs. (Pictures taken by 4-megapixel SLRs are used professionally, like on calendars and ads, though, so you REALLY don't need more than 4).



I hope these pictures keep you from blowing a fortune on a super-high-resolution camera. THIS IS A VERY IMPORTANT POINT: Don't buy more megapixels than you need, and don't let the camera companies' marketing departments tell you how much you'll need. Three or four megapixels is all you need, even for 8x12s and for some cropping if you're gonna get 4x6s. Sure, 5MP images might be sharper, but unless you print them out huge, or crop a lot, you never even really get to see all that detail. So if you're thinking about a 5-to-8 MP camera, consider getting a 3 or 4 MP camera instead, one with a sharp lens and a not-too-noisy sensor, or a smaller camera, or one with a bigger screen, etc.

As I mention a few times on this page: How sharp the lens is, and how grainy the sensor is, can affect image quality even more than resolution. So there's much more to it than megapixels. As you can see in the "Don't buy more megapixels than you need" section, a camera with more megapixels can sometimes deliver lower image quality!!! (You can click here to go straight to the comparisons that show this.)