Metabones Speed Booster - Vignetting with Tele-Lenses

Here are OOC JPG images, successively being stopped down, starting wide open, for this configuration:

Sony NEX-5N with EVF + METABONES L/R-E mount Speed Booster + Leitz Ring 14127 + Short Focus Mount 16464 + Tele-Elmar lens head 135/4 + Hood 12575

Focus was on the weeds in the center foreground, ISO=100.

1/6s

1/4s

1/2s

1s

2s

There is considerable vignetting wide open.  The image quality improves at the edges and in the corners as one stops down from 4 to 5.6, 8, 11, and 16.

Best, K-H.