Quote Originally Posted by Kayaker72 View Post
Maybe a touch more vignetting than the Mk II. But even stopped down to f/4, that is basically perfection on a 50 MP sensor.

I like to look at superteles with TCs on them as, 1) that is how they will be used, but 2) it is likely to accentuate any flaw.
Not too long ago we switched lighting systems for the test chart. We previously used Canon Speedlites set to TTL; now we use Flashpoint XPLOR 600PROs which are also set to TTL. We haven't completed enough tests with the new lights to be confident that they light the chart evenly each and every time. Therefore, the vignetting tests (to be published soon) will be a more precise indication of vignetting performance.