Most people strive to end up with an image can be printed large enough to go on a postcard (at the minimum) without losing any quality. Sharpness, image quality and resolution are not always related although each of them individually will impact overall image quality.

Pixels are essentially little dots and they make up a picture, they are arranged vertically and horizontally and if you get close enough to any screen you will begin to see them.

Image resolution is how many pixels there are counted vertically and horizontally. A 3MP camera has 2,048 pixels horizontally and a 14MP camera has 4,500. They have fewer pixels vertically as the images aren’t as tall as they are wide. Image resolution is different to print and screen resolution as they are both applied to a linear unit (ie. something that is fixed).

PPI (pixels per inch) and DPI (dots per inch) are the two acronyms used to represent resolution. PPI is to be used to describe a digital image or output such as a monitor, TV or digital camera. DPI, being dots, is to be used to describe and analogue format such as print.

A megapixel (often abbreviated as “MP”) is one million pixels, so when a camera has “10MP” is means it can effectively produce an image that contains 10 million pixels in total. When searching for a new camera, megapixels seem to be the deal breakers, as though a higher megapixel count will result in better images. While megapixels are important, there are many other factors such a lens glass/quality as well as user competence equally, if not more important.

For perspective, most computer monitors will only display up to 8MP of resolution and even a file produced by a 20MP sensor is able to be printed at 18” wide without any upscaling. It may be worth considering how often will you be printing 12x18” photographs!