If you aren’t careful, you can find yourself caught up in one little number as you shop for digital SLR cameras: megapixels. But digital cameras have come far enough that the megapixel isn’t the most important feature to maximize within your budget, not by a long shot. So what’s in a megapixel and how many do you need? Understanding megapixel and photography basics will make it easier for you to choose the right camera for your goals and budget. Put simply, you don’t need more than five or six megapixels.
Unless you are printing photos at mammoth sizes of more than 11×14 inches – you’re probably a pro and already know how many megapixels your uses demand – you won’t be able to see any difference in image quality or crispness in your prints or on a monitor if you go above that threshold. However, even budget point-and-shoot digital cameras for a few hundred dollars feature sensors with more than 12 megapixels, and 20 is easy to find. So the first point is to realize that as an amateur photographer of almost any level, you don’t need to concern yourself with finding a camera with enough megapixels for your need.
Just for the sake of completeness, take a look at a few options and the rough megapixels-price ratio as of Fall 2013. At under $150, you can get a simple hand-held with minimal features and 16 MP. Move up to around $350 and you have access to the range of Canon Powershot cameras and their Nikon competitors, which have between 12 and 15 MP and a host of other features. 
The most popular introductory DSLR cameras, like the Canon EOS Rebel SL1 cost between $600 and $800. About that same price gets you an intro-level digital SLR camera kit with somewhere around 18 to 20 MP. The same rough number of MP, 18-20, is present in the next tier of DSLR cameras priced around $1,000. Then at the top of the range, you find housings priced anywhere from $4,000 to $6,000 and up for just the body, offering anywhere from 18 to 22MP with little correlation between price and pixels.
So not only do you find not much correlation between price and megapixels except at the very top and very bottom of the price range, but if you’re like most amateurs you really don’t care about these differences. Most people will never do anything with their photos that would allow them to see the difference between 16 and 22MP.
But for the sake of argument, consider what you get if you do spend the thousands necessary for something like the Nikon D800, which boasts a whopping 36.3MP. On the one hand, you do gain a bunch of flexibility. This digital SLR camera captures shots that you can crop for days without sacrificing resolution. If they can blow up to multiple feet in dimension, it means you can crop down to a very small space, expand it to the desired print dimensions, and get a crisp photo.
However, there is a tradeoff at the top of the range. Sensor sizes on non-full-frame housings haven’t gotten larger, which means that to squeeze 36.6 million pixels on the same space each one must be much smaller, and thus captures less light. This can give pictures a grainy appearance due to higher image noise, especially with higher ISO settings.
In summary, megapixels are important for the quality of photos taken with digital SLR cameras, but you probably shouldn’t use them as a metric when shopping for a new camera. Nearly every camera on the market has enough pixels to meet all your needs, and you can end up paying a lot more to achieve top-of-market numbers while maintaining the overall quality of the camera.
