How Many Megapixels Does Your Camera Need?

People contemplating the purchase of a digital SLR often agonize over how many megapixels they should buy, even though you may find other factors (such as ease of operation and the kind and quality of lenses available for a particular dSLR) considerably more important in the long run. To a certain extent, vendors have (at least temporarily) alleviated this agony. In the past year or two, a surprising number of vendors have settled on 12MP as a basic benchmark number. Nikon, for example, has three 12MP digital SLR cameras — a basic entry-level model, an intermediate amateur camera, and a feature-packed advanced model that both serious amateurs and professionals love.

Canon, too, has introduced several 12MP models, and other vendors have followed. Of course, for most applications, you don’t really need more resolution. But, with competitive pressures being what they are, I don’t know just how long the 12MP plateau will remain the standard. (I urge those of you reading this in 2012 with your $499 21MP cameras to refrain from laughing.) Although more pixels usually equal more resolution and more detail in your pictures, the number of pixels you actually need depends on several factors:

✓ How you plan to use the photo: An image that you place on a Web site or display in presentations doesn’t need to have the same resolution as one that you use professionally — for example, as a product advertisement or a magazine illustration.

✓ How much manipulating and cropping you plan to do: If you want to give your images quite a workout in Photoshop or you often crop small sections out of images to create new perspectives, you want all the spare pixels that you can muster because high-resolution images can withstand more extensive editing without losing quality than low resolution images can.

✓ How much you plan to enlarge the image: Many people view most of their images on a computer display or in 4-x-6-inch to 5-x-7-inch prints. Any dSLR has enough megapixels for those modest applications. If you’re looking to make blowups bigger than 8 x 10 inches (for example, to make posters or prints that you display on the wall), you need a plethora of pixels.

✓ The resolution of your printer: Most digital images are printed on inkjet or dye sublimation devices that have their own resolution specifications, usually from 300 dpi (dots per inch) to 1440 dpi and beyond. Printers work best with images that more closely match their own ability to print detail. If you primarily want to create prints, the following section can help you gauge which capabilities you need in your camera and printer so that you can get the best output possible.