Hey guys , if your getting vignetitng try a 2" 40mm Kellner EP with your digital camera.
I have a Minolta D7 and they have a very large front lens and had this same problem .
I modified a cheap kellner EP from Andrews , before there was the scoptronix solution . A lot cheaper than Scoptronixs as well.
This EP has a large lens and , and if you machine off the end almost down to the lens you won't get any vignetting in Afocal mode.
You need to get the camera and EP as close as possibe.
See the link below.
http://www.iceinspace.com/forum/show...0&pagenumber=1