[UV] A surprising lens without UV focus shift

Well, I am studying lenses since quite some time and was researching the history of some, when I noticed the same reflection pattern (which is a hint for the lens design) in an previously overlooked lens I have...

Well, I tested it good for 330nm in my spectrometer and in theory it should have no focus shift (or just a tad)...

So best is always to try it out, so here some first tests!

[click on image to see a larger one]

VIS: 


UV (Baader U-filter, 310-390nm):


Long story short - it has hardly any visible focus shift!

Look at these mites and  fine webs!! Pretty fine resolution it has.

More about it later ... and sssshhhh, that lens is a secret until then ;)


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