From the way I see it:
Metering in manual mode can be a learning tool, teaching you the fundamentals of reading light, tonalities & exposure, If I'm thinking correctly.
In a way starting out learning manual by first metering (evaluative), a nuetral toned constant in the enviroment (grasses for example), (This is also good practice consistantly choosing nuetral tonalities), and nulling the meter to zero. Then by taking mental notes of where the meter scale is when you compose your subject.
Lets say the nuetral toned female shoveler is swimming in the light blue water. Your meter now indicates about 2/3 a stop or better over the 0 scale mark from your (nuetral tone @ 0) base exposure. So that just basicly taught me that the duck in the light blue water exposure is about 2/3 or better stops over a nuetral tone with my camera correct?
So having that experience prior, If I didn't take a metered base exposure and just composed on the fly, I would assume +2/3 stop over 0 and have nailed it. With a highlight alert or histogram check afterwards to verify or push it a little. So either way I metered, the exposure would be the same, correct?
And of course I mean this by metering from a nuetral constant, then paying attention to where the meter is resting when I frame & shoot. Though my subject is exposed the same with varying backgrounds, with the meter jumping up and down it's teaching me or giving me references for compensations. I'm just wanting to know if I'm on to something, or getting this.
I know I can also get a base exposure from the sky, or snow, water, ect. But I think for learning and becoming more competent in manual basing exposure closer to a nuetral tone is best, for me perhaps. I'm also teaching myself more on learning the Sunny 16 rule to apply.
Hope I'm on the right track, and look forward to comments.
I been trying to learn manual & really inspired by photographers like Jim Neiger, Artie, O'tool, Gamez, Glatzer, I could name so many more that are here in Bird Photographers.Net. It's a wonderful place to learn and although I read here alot I don't participate as much as I maybe should. Thank you all for all the hard work you do and the help you offer others.