FRACK hunting bugs

Experimenting with the Sigma 50-100mm f1.8. It's designed to cover aps-c but is EF mount. I decided to mate the lens with a Meike Speed booster to see if the bokeh changed much. Short answer, yes there is more swirl and vignette. The sharpness takes a hit but I like the rendering. I'll definately be experimenting more with this lens.

Done