I manual focus a lot but only with my old MF lenses. Trying to manual focus a camera and lens that's built for auto-focusing is a pain.
Ken mentioned choosing the right process for the shot but you also have to choose the right process for the
tool. Modern DLSR's and lenses are designed to be auto focused. They removed the split prism focusing aid from focusing screens to allow a clearer view but this also makes manually focusing more difficult. They shortened the focus throw in lenses to speed up AF but it also sacrifices precision during MF. The smooth damped feel of a MF focusing ring is also very hard to achieve with a focus ring that is now attached to a set of gears. It all adds up to a less than satisfactory manual focusing experience. I understand that it is necessary in certain situations, but I wouldn't want it to be my normal modus operandi.
This is why I ended up modifying my camera when I started using more manual focus lenses (added a split prism focusing screen). Make my tool fit the process.
