A lens measurement would have to be conducted in a controlled environment with a test chart, and I'm sure that it would be similar to MTF testing ("evaluates a lens' performance, and its contrast sensitivity"). There are a number of free test charts available, and I would personally use a test target in a box like I saw one someone's web page. The photographer pointed the camera into the sun, and photographed the test target inside of a box. He did it with and without a lens hood.
Originally Posted by RalphLambrecht
On the LFPF, we had a discussion about "bokeh," and I facetiously came up with the Drem Glasgnademeter and Leica Glasgeistometer. Later I came up with a set of possible measurements. I suppose things like flare and contrast control could be valid parts of that measurement.