The lens is Nikkor 20mm, 1:2.8, used originally with a Nikon 801. A high quality lens in its day and, yes, you could easily find your feet in the shot.
Digital SLR is a Nikon D90 for which I have only one lens, a standard 16 - 85 mm.
The old lens fits on the new camera but the results were so poor I resigned that one just wasn't designed to work with the other.
Interestingly, the 16mm on the D90 shows very little difference in aspect to when the 20mm is mounted on the D90, just as you describe for APS-C cameras.
I could post some sample shots when I have more time.
