I've heard people say that everything meaningful about a lens's optical performance can be determined simply by looking at the MTF charts — although nothing is mentioned of that under How do I interpret an MTF Chart? or for that matter What is bokeh, exactly?
I heard something about the distance between the lines on the chart, and their divergence or convergence.... Is it true that this can be used to predict whether a lens will render "good" bokeh or bad? (Note that I'm not talking about amount of depth of field, but rather the visual quality of the out-of-focus areas.)
The Pentax DA★ 200mm I'm trying out has generally nice bokeh (and gets lots of praise for that online) but in some situations I've noticed that it it's got a clear ring shape on highlights, rather than being perfectly smooth. Could I tell that from an MTF chart? And, if a "real" MTF isn't available, can I tell it from the MTF bar graphs given in some online reviews? (That is, do the line graphs show something these bars don't?)