It is a macro lens, transformed, super bright and difficult to handle, and it works the same in its normal position as when turned upside down, inverted.

In comments from a few years back—2019 or so—Roland opined that the 6 element/6 group variant of Nikon’s 35mm f2.8s for the F was likely the best, optically. I have an unorganized collection of the more common pre-auto focus F lens, and exploring this claim has been on the agenda for some time. I got to it last week...the usual ad hock test including tripod and common subject (a street sign), distance, and lighting. So, yes, the 6-element version of the 35 2.8s (i.e., the early AI variant, which also sold as a K lens) appears to be the best, notably in the corners at all apertures. Interesting to me is the successor 5 element lens (late-AI and AIS): it’s pretty good, despite the simple optimal performance. I should mention also that, for resolution, the original 35mm f1.4s—in this case, an early production sample (#351676)—seem to be at least as good as the 2.8s, for apertures f2.8 – 8.0.   

You have made it - well done.

Are you going to refine the plastic adapter into metal and develop it for greater ease of focussing?

Thanks, Hugh, your idea was crucial. I can't yet assess the ingenuity; when I have more tests, I'll consider the lens's usefulness.

3, D200

Examples of the invention.