I did some tests last night with my TL120 and a 55mm Mamiya
lens. What I found was the farthest focus achievable with
an un-modified lens was 3.4m Trying to focus farther out
was impossible due to interference between the rear lens
element and shutter frame.

I also noticed that as the finder does not have a shutter in
front of it, it is possible to focus the viewfinder to
farther distance than can be done to the film plane.
--
John Thurston
Juneau Alaska
http://stereo.thurstons.us