Resolution 101

What is resolution? Resolution describes the detail an image holds. In order to understand resolution, you need to understand what digital photos are made of.

Every digital image is made up of millions of tiny squares called pixels. Pixels are arranged horizontally and vertically within an image, and if you zoom in close enough you can see them. The more pixels a photo has, the higher the resolution becomes.

Resolution can be measured by using the pixel dimensions of the entire image (such as 1500 x 1000 pixels) or it can be measured by the number of pixels per inch (PPI) relative to the printed image. Digital camera manufacturers measure the resolution of their cameras in megapixels. One megapixel is equal to one million pixels. The megapixel measurement is figured by multiplying the pixel dimensions of a digital image, that number is then divided by one million.  For example, an image that is 2000 x 2500 pixels has a total of 5,000,000 pixels, which means that it is a 5 megapixel image.

Camera makers use the number of megapixels a camera has to mislead you into thinking it has something to do with camera quality, but in reality it is only one aspect of what will make your photos look good. For example, 3 MP cameras have 2,048 pixels horizontally and 14 MP cameras have 4,500 pixels. (They have fewer pixels vertically since the images aren't as tall as they are wide.) That's not much of a difference, is it?

It seems logical that more megapixels would mean a sharper photo. In truth, though, it could just mean a terrible photo made of more pixels. A camera’s lens, circuitry and sensor — not to mention your mastery of lighting, composition and the camera’s controls — are far more important factors.

Are we saying that Megapixels don’t matter?

Not exactly.

First of all, having more megapixels can be extremely useful in two important situations: cropping and enlarging. You can crop out unwanted background and still have enough pixels left for a decent print, or enlarge your photo to poster sizes and not have to worry about pixelation.

Our chart below will help you figure out what size prints you can make from your digital camera

Camera Megapixels Largest Recommended Print Size
4 to 6 MP 16" x 20"
8 MP 20" x 30"
10 MP Poster size

Keep in mind that these guidelines are not absolute! Your lens, lighting, CCD quality and method of printing all play a part in the final results.