In theory it would make a wide angle, but I have never tried it.
You could get image-degradation because this Rolleinar is not designed for the 80mm Planar/Xenotar.
My 0.70x Tele Rolleinar lives on my
2.8C -- it's just enough to get just
close enough, without introducing
perspective distortion. And it's much
easier to mount and dismount than
the conventional 2-piece Rolleinar.
I've shot thousands and thousands
of frames with this combination. I've
yet to see any degradation in lens
performance.
It is the same as a regular Rolleinar,
only 1/3 weaker. It does not widen
the angle of view, but it does limit
your ability to focus at distance.
Sanders