Metabones Speed Booster - Vignetting with Tele-Lenses

I tried the Metabones Speed Booster on an NEX-7 with the following two lenses:

Leica APO-Telyt-R 1:4/280
Sony NEX-7 + Metabones Speed booster + Leica APO-Telyt-R 1:4/280 @ ISO=100, 1/4000s, f=4, processed but vignetting not corrected

Sony NEX-7 + Metabones Speed booster + Leica APO-Telyt-R 1:4/280 @ ISO=100, 1/4000s, f=4, processed and vignetting corrected

Sony NEX-7 + Metabones Speed Booster + Leica APO-Telyt-R 1:4/280 @ ISO=100, 1/2000s, f=4, OOC JPG

Leica M9 + Novoflex Adapter M-R + Leica APO-Telyt-R 1:4/280 @ ISO=160, 1/1000s, f=4, OOC JPG

Sony NEX-7 + Novoflex Adapter E-R + Leitz 14127 Adapter + Telyt-V 1:5.6/560 @ ISO=100, 1/500s, f=5.6, OOC JPG

and Leitz Telyt 1:5.6/560

Sony NEX-7 + Metabones Speed Booster + Leitz 14127 Adapter + Telyt-V 1:5.6/560 @ ISO=100, 1/500s, f=5.6, OOC JPG

Full resolution images can be found here:
http://winklers.smugmug.com/KHW/Pics-by-Date/2013-01-16-Speed-Booster/27591952_X3mbQ2#!i=2325281653&k=fjj22B9
http://winklers.smugmug.com/KHW/Pics-by-Date/2013-01-17-SpBoosterVignetting/27611114_MjQqmT#!i=2325208615&k=Gh5fxPc
With best regards, K-H.