This is when I first got it. Sankor with Nikon 55mm F2.8 taking lens (forgot I had the Helios) but same idea. Didn't use nd's, just stopped down. Haven't had the chance to really put it to use since. Straight from GH2 to PP CS5.5 and export.
Sorry, vignetting was only from the taking lens I was using which was a Macro lens that has a deep hood design. The Helios does not exhibit this, additionally, if I actually angled it correctly it wouldn't have showed on the Macro lens either. I got it the night before, slapped it on real quick and shot those real quick before arriving to work to review it.