5. How Many Megapixels Do I Need? (continued)

So how many pixels are enough? As noted previously, it depends on what the photographer wants to do with the final image. For emailing home pictures or adding images to a web page, virtually any digital camera is adequate.

However, if the end result is quality color prints a higher mega pixel rating is preferable.

The chart below serves as a general rule-of-thumb guide to printer output sizes in mega pixels.

 

Dots Per Inch (DPI) explained

I previously mentioned the term DPI (dots per inch).  The term DPI is often used in photography, printing and video displays, and quite often the term is used interchangeably or even incorrectly.

For the sake of this guide, DPI is intended as an output resolution for printing digital images.

For example, consider the previous example of Nikon D80 at highest picture quality setting of 3872 pixels x 2592 pixels.  If the resulting jpg image is printed directly at its native 300 DPI setting, the resulting print will we 8.5" x 13".  If the image is enlarged (in Photoshop, for example) to 4272 pixels x 2848 pixels, the resulting 12 mega pixel image that would print  9.5" x 14" in size.