Yesterday’s flash seminar at Vistek reminds me to warn you about one of TTL’s drawbacks.
Usually, metering is “evaluative” (Nikon calls it “Matrix metering”). Good. Even good for tough chiaroscuro lighting like in these pictures from the course (one flash, off camera):
But that metering method, while generally very good for tough shots like those, has one possible drawback. Namely this: one small reflection will lead to the entire photo being underexposed, since the metering system tries to avoid overexposing that reflected area. And with evaluative/matrix metering (“smart” metering), even a tiny area can cause that problem. As in this image:
Ouch. Yeah, that got me. So then I remove the reflective object and all is well:
This happens, and you need to be aware and ready. So why not go to centre-weighted flash metering? Yes, that is an option, but then pics like these will be averaged out, which is also not what you want!
And all that is why light and metering and the other technical aspects of photography are not about to go away. A billion iPhones notwithstanding: you need to learn this stuff to be able to do any creative photography.