alwang wrote:
Are you saying the tubes caused field curvature, which the extender avoided, or are you saying the 50MP has field curvature, which the extender corrected?
Not really either one of your options, closer to 2nd option if it would be mandatory to choose.
"Bare" lens when used outside makro/close-up range has very steep field curvature in corners. 2x extender basically magnifies center part of image, and due to it gets rid off field curvature. Lens doesn't have significant field curvature on makro range, as the lens extends and smaller part of projected image circle is recorded by sensor/film.
Greggf wrote:
Looks good to me, Werner! But that 18 has got to be very front heavy, especially with the III adapter too!
Gregg, Metabones III has Arca-Swiss profile in bottom, any EF lens is great on tripod.
Samuli