How many megapixels are required for 4×6″, 5×7″ and 8×10″ prints?
For high quality prints (at 200 ppi), the camera should have the following megapixels (MP): • 4×6″ prints require at least 1.1 MP • 5×7″ prints require at least 1.5 MP • 8×10″ prints require at least 3.9 MP If you will be doing significant cropping of the photos (digital zooming), more megapixels will be required to make up for discarded pixels. For additional details, see Megapixels for Digital Photo Printing.