Tuesday, January 26, 2010

A Study of 50 wide + normal Lenses for UV Photography

[click on image to see a larger one]
Over the last many months I have been researching some shorter focal length lenses (wide + normal) for reflected UV photography. Without much ado, here the results I found condensed into one graph. The right grey part of it shows where the lens transmits UV, the blue bar to the left where the lens blocks UV. Border was set at a -3EV transmission level (12.5% relative to the maximum transmission).
Personally I would rate a lens useful for UV, if it allows UV to transmit at least to 350nm. Bare in mind, that the available DSLRs today hardly even reach that far, the deepest I could ever record in UV was 320nm, which perfectly matches these available lenses.
This is far from being a complete list of course, but the idea behind that was to prove, that older lenses still have their right to be used today with modern digital cameras, since they have abilities, modern lenses often lack.
To be clear, a high UV transmission is just one prerequisite for a lens being able to be used for reflected UV photography - but the most important one. Further selection criteria must be sufficient high resolution and contrast, flare resistance etc. which would certainly narrow down the list of candidates. More about that later here...
[Most of these lenses don't have Nikon mount, so using adaptors would only allow their use for macro work. But some of them can be either converted dircetly to Nikon mount allowing infinity focus or by using a special UV enabled adaptor. Contact me, if that would interest you...]
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

Monday, January 18, 2010

X135 supports Transmediale 2010 Art Project "Invisible Cities"

In a few days the Transmediale 2010 Exhibition will open its doors in Berlin, Germany. A very creative young artist, Julius von Bismarck , will be  showing his newest art project there, the follow up of his "Fulgurator" and a very creative new piece of art as part of the "Invisible Cities" presentation named "The Space Beyond Me"

[simulation of the 2D film panorama developing based on pattern recognition as can be seen on the down left small image, not visible later. Idea, concept and realization as well as that image (c) Julius von Bismarck, Berlin, Germany assisted by Andreas Schmelas, computer programming]

There, a film will be projected to a circular projection screen. Nothing new you think? Well, I guess very much so, since it does not happen in the visible world, but the projected light is invisible and, you may have guessed it already, it is ultraviolet. The screen is covered with a fluorescent + phosphorescent substance, so when hit with UV light, it radiates visible light.

Now the very special idea of the artist is, to use that screen as a short term memory to develop a two-dimensional panoramic image of what is stored on that film on that fluorescent screen by detecting the structures of objects and subjects in each frame of that film and assigning it to a fixed position on that phosphorescent screen (so the film projector moves in two dimensions to "write that information on the wall" using some special software and 2D stepper motors which control the position of the projector). So frame for frame, the panorama develops on that screen, until finally all information contained on that film has been displayed and temporarily stored on that fluorescent screen until it fades away....

((quote)) The Space Beyond Me recreates a process in the human brain in which virtual three dimensional images are reconstructed from two dimensional information; a principle that enables us to vividly imagine a place where we have never been before, or a time that is already history. ((unquote))

And what has that to do with the X135 lens? Well, an affordable lens able to project a very sharp and contrasty UV image was needed by the artist to allow that fluorescent screen to function well (= bright enough). So a few tests I have conducted clearly showed, that compared to a normal camera lens, the X135 is able to project an image more that 100 times brighter. An X90 was also tested with the same good result.

In my former BLOG entries ("Thoughts about Lenses and Filters" and "Normal Lenses for UV"), the principal difficulties have been discussed and showed how to overcome these.

So if you have a chance to visit Berlin in February 2010, make sure to pay that very special event a visit!

See you February 7nd, 2010 in Berlin at the TRANSMEDIALE in Salon/K1!  Exhibition schedule is here (pdf).

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