I'm a new member of this forum. I got interested in photography about a year ago, so I'm pretty much a beginner. I've been reading some of the great tutorials on this site and I have a question about the one on autofocus ("Understanding camera autofocus").
In the middle of the text, it says:
But a bit further down it says:Further, since the central AF sensor is almost always the most accurate, for off-center subjects it is often best to first use this sensor to achieve a focus lock (before recomposing the frame).
To me this seems to be contradictory. Which one is correct? If it's the second, then I would like to understand why this is the case.Although the central autofocus sensor is usually most sensitive, the most accurate focusing is achieved using the off-center focus points for off-center subjects. If one were to instead use the central AF point to achieve a focus lock (prior to recomposing for an off-center subject), the focus distance will always be behind the actual subject distance—and this error increases for closer subjects.