Understanding picture resolution

Resolution, and in particular, photo resolution, is a feature that confuses many beginners. This shouldn't really be an issue because the resolution of a camera is a fixed quantity and will only change when you choose a different image size in the camera menu, or if you crop the file on a computer. But to be pedantic, resolution is not only to do with the number of pixels in the camera, or in a file, although this is important. Resolution is also connected to the quality of the glass elements in a lens, the camera's image stabilization technology (indirectly), and the camera technique employed by the photographer. The biggest point of confusion comes with the way the number of pixels per inch (ppi) can vary widely from camera to camera. Note that, in the printing world, dots per inch (dpi) is the same as ppi, which in turn is the same as lines per inch (lpi).

Because so much work is displayed onscreen these days, it is hard to accurately illustrate...