Thursday, November 15, 2007

The strangest lens for UV I ever found...

Today it is about one of the strangest lenses for UV photography I ever found: a Wollensak 4" f4.5 UV Anastigmat and that is its fascinating story (which I have been told by the former owner and will now be put forward as it came...):

"Late in 1950 there was a number of large iron metorites that landed in the northeast of the United States. Upon examination a great many had a solid and perfect core of a crystalline substance that resembled the finest of optical glass. The owner of Wollensak being a man of quirk and varied interests decided to purchase a number of the meteorites and to saw them, grind and polish them to make a few lenses. The meteors were quite large but the glass was quite brittle so in the end only a few lenses were made...this being THE one, the finest, the 'sample' of the series.

The lens seemed to have a fire within itself, no doubt due to the experiences and conditions that the crystal was made..flying at untold speeds for untold millenia over millions of miles. The sky is a big place, the galaxy is even greater. This lens...oh this lens, is something very special. It seems though to have been at the center of a number of accidents at the factory.

While the cutting took place, a shard flew from the block and pierced both eyes of machinist, later during the polishing process a young apprentice caught his sleeve in the polisher which broke his wrist then as he struggled with his other arm in a vain attempt to free himself he managed to catch that one too. It snapped like a twig, he fainted and fell forward at which point the collar of his shirt was caught in the polisher and it snapped his neck.

Truly a sad tale of woe which cannot be entirely brushed away with coincidence. While the lens was being coated it was noted through the window that the magnesium fluoride wasn't melting so the technician entered the oven to adjust the thermostat only find that the oven was on, in seconds his clothing was on fire and he was completely disfigured. While all this commotion was going on small chirps were heard to come from the lenses, some say it was the glass contorting in the mounts while others was the lenses laughing."

Here now the results of using this lens, first the visible shot:

And this is the UV shot using the 2" Baader U-Filter (310..390nm); that lens is not corrected for UV focus, so finding a sharp image is somewhat tricky:

So what have we here now? This is a differential between the two shots above, showing in one picture compressed the visible light and the UV shot. It clearly reveals how metal strongly reflects UV, and so does the sky:

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site