Thanks Tim, very informative. I have started out mostly using the manual mode, only because the first serious photographer I have met after purchasing a DSLR, uses manual pretty much all of the time. We are usually shooting landscapes, some water, and a lot of sunrise/sunset photos. My question is, is there a problem with mostly learning on manual mode as a beginner?
" ... is there a problem with mostly learning on manual mode as a beginner?"
Sure there is, you don't understand it. You don't understand how metering works using the system built into your camera. You don't understand "exposure".
Why make life harder on yourself than necessary? At this stage in your learning curve, there really is no advantage to using full manual mode. There is a downside however.
First, there is no "correct" exposure for any image. There is only the exposure value which does not blow out highlights or darken shadows so completely they cannot be used for detail retrieval during post production.
IMO, you're looking at the wrong feature of your camera. You don't need to be using manual mode and you certainly don't need to copy another photographer's work mode. If their system works for them, that's their business.
Learn instead to work with the histogram, not the exposure system. True, they are linked with each other but, looking at only one ignores the other. And, IMO,
the histogram is the far more important feature of any modern DSLR.
If you are using a digital camera of any sort, you will need some form of software to process the photos for printing and, possibly, for posting to another computer. Most modern software can easily compensate for global exposure values and the better programs can even do spot adjustments to any specific region of your image.
So, a big "nyah-nyah" to those who are complaining about the exposure of your images. Even shooting Jpegs, you can adjust exposure values with the least powerful software. Yes, of course you should learn what a "proper exposure" looks like. The problem is, there is a very wide latitude in what is correct exposure. Until you lose either highlights or shadows, exposure is what you care for it to be. Even more so if you only shoot Jpeg's.
The issues become whether you are losing detail, they are not overall exposure values. You can only judge this value by observing the histogram of the image before you snap the shutter release.