Manual focus is earliest way for focusing based on handly rotating a focus ring on lens. MF is sometimes unhandy and hard to use but with great availabity in macro, speccial effect and low light photography. Manual focusing is also great help in situation when AF does not work well. Also i want to noticed that most of compact cameras with manual focus function does not have a real manual focus. That cameras use a AF mode to choose a real focus point and then just going + or - from that point simulating the real manual focus.