Third Party Manufacturers / Re: Have a NEX body? Make your EF lenses sharper and faster! - apparantly« on: January 14, 2013, 04:18:09 PM »
Sorry, but not the same thing for me: one reduces the image circle, the other enlarges it.
Which are you saying enlarges the image circle? This adapter and what I described take a full-frame image circle and concentrates onto a smaller area (the size of a crop sensor). This has two effects: the light circle is brighter, and the crop sensor now has a similar angle of view through that lens as if it were a full-frame sensor.
.71x focal length means the focal length is 71% what it was before.