Monday, February 21, 2011

White Lilly - a surprising lens find for UV and VIS w/o focus shift II

Well, a while ago I was doing these "Psychedelic Lilly" test shots here . Prior to that I had taken UV transmission tests of that very interesting lens family, which turned out to be very promising, reaching down to about 320nm (-3EV). Here now more about that.


These macro shots were done at f8, ISO400, 1/160s using Xenon flash, exposure adjusted using flash power control and ND filters. UV shots were done using the Baader-U filter.

[click on image to see a larger one]

Here now a VIS-UV differential:


quite a sharp lens with quite good UV transmission and hardly any focus shift, as the two overlaid images nearly perfectly match!

Here the VIS shot:


and the UV shot:


Finally now the VIS-IR differential:


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

[UV] EL-Nikkor 80mm for UV - old vs. new type

As I was testing (again) lenses for UV photography, I had done spectrometric tests on Nikon EL-Nikkor enlarger lenses. The question arose, if the newer 80mm EL-Nikkor has as good an UV transmission as the older, full metal type. So now since I found a new one, here the comparison transmission graph old metal one vs new plastic "tyre like" version. Both are f5.6/80mm.

[click on image to see a larger one]

UV transmission graph:


In terms of UV transmission, quite a substantial difference of about one stop in favor of the old type I would say. The newer one seems to have some fancy new multicoating, which brings the transmission losses in the visual range substantially down, but the UV transmission has been quite reduced by doing so.

P.S.: the 80mm EL-Nikkor (the older, chrome black full metal type) has an adapter ring on its base with outer M39x26tpi screw mount (Leica enlarger mount). Beneath it is a M25 thread for older #00 shutters. Company Schneider Optics offers adapter rings, if that one should be missing (oder code 92-013251).
P.P.S.: the filter thread of that older EL-Nikkor 80mm is 34.5mm, which is pretty uncommon, ask me if you need an adapter ring.

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