Philip Dunn ansers the question I would have asked

On his blog, photoactive, pro photographer Philip Dunn answers a question about manual exposure from a former student that addresses exactly the issue I ranted about two posts ago:

When you are using an automatic exposure mode such as Aperture Priority, ... every time you make an adjustment to the your framing of your composition the chances are that the exposure will change as the metrering system reads from a different area of the subject.

This is precisely why I cannot be bothered with auto settings.

I want to take my reading from the area of the subject I choose and for that exposure not to change when I re-frame the picture.

To keep this in perspective, Dunn also wrote the following, in the tutorial on manual mode he posted this Sunday:

Never let setting the exposure get in the way of capturing the moment. ... If you think you are going to miss a picture – revert to Auto Exposure mode. It’s the picture that matters, not the way it’s exposed.

To summarize, I was more or less on target when I said that the right reason to use manual mode is that you think the lighting conditions affecting your subject are unlikely to change quickly between shots, and that auto mode is justifiable when this is not the case.

Philip Dunn, being a highly experienced pro, advocates practicing with M mode until you are fast enough with it to use it most of the time. ("You will be surprised how quickly you will be able to set your exposures manually.") I'd say that's a matter of taste, except that his "taste" is the result of years of success taking pictures, while mine is the result of not having had years of success taking pictures. You figure it out.