As I was testing (again) lenses for UV photography, I had done spectrometric tests on Nikon EL-Nikkor enlarger lenses. So now I found a new one in my lens set, so here the comparison transmission graph old metal one vs new plastic "tyre like" version. Both are f4/75mm.
[click on image to see a larger one]
UV transmission graph:
In terms of UV transmission, a neglectable difference I would say. Could that result serve as an indication that also the other EL-Nikkors in newer plastic "N" version are that close in transmission? I would be rather careful about that. Maybe, maybe not.... we'll see ;)
Stay tuned, more will follow on that fascinating subject...
More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos