A Question About Manual Focusing

[wiltw]

Most of the time you can focus within the clearer central area and then recompose because the distance from subject to film plane isn't changing that much when you recompose. The situation to be careful with is wide apertures and close distances because then the shift is likely significant. For example, if you're making a portrait and focus on the subject's eye, then recompose, it's likely the resulting image won't have the eye in focus. In cases like that, you'll want to do your final composing first and then (without recomposing) adjust the lens focus so that the eye is sharp wherever it happens to be be in the viewfinder.

As illustrated in post 7 chart, if you keep the angle of change to under 10 degrees, generally DOF zone depth saves your bacon on focus-recompose error in focus.