35mm BESLAR enlarger lens for reflected UV photography

Today again about a simple, but as it turned out, quite UV capable BESLAR f3.5/35mm enlarger lens. I have done a similar enlarger lens comparison for a 100mm lens here and here and a comparison for 50mm lenses previously here. I'm using a yellow/red Phalaenopsis flower for that and my "work horse" UV filter, the Baader-U filter plus the deeper reaching Jupiter-U filter. Light source was an UV enhanced Xenon flash. All shots were done at f8 and are presented in a side-a-side format for easier comparison.

[click on image to see a larger one]

Images showing on the left a visible light image and on the right using the Baader-U filter (approx. 320-395nm, effective peak approx. 375nm):
 

UV images using shown on the left the Baader-U filter (approx. 320-395nm, effective peak approx. 375nm) and on the right my Jupiter-U filter (approx. 280-385nm, effective peak approx. 365nm):
 

UV detail images using shown on the left the Baader-U filter (approx. 320-395nm, effective peak approx. 375nm) and on the right my Jupiter-U filter (approx. 280-385nm, effective peak approx. 365nm):
 

Transmission graph:
 

Well, this little enlarger lens performs acceptably well, seemingly has quite a high UV transmission of about 80% and quite a deep reach into the UV region to about 320nm (white line), compared to my new standard 35mm lens (green line), the Kuribayashi 35mm. I also tested a rebadged version under a different moniker (pink line) which seems to perform about identical.


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

Steinheil Cassaron 40mm vs Kuribayashi 35mm for reflected UV photography

Here today a comparison between the well known Kuribayashi f3.5/35mm lens and the lesser known Steinheil Cassron f3.5/40mm lens. I'm using a yellow/red Phalaenopsis flower for that and my "work horse" UV filter, the Baader-U filter plus the deeper reaching Jupiter-U filter. Light source was an UV enhanced Xenon flash. All shots done at f8 and presented on a side-a-side format for easier comparison, left the Cassaron, right the Kuribayashi lens.

[click on image to see a larger one]

Visible light image:
 

UV image using Baader-U filter (approx. 320-395nm, effective peak approx. 375nm):
 

UV image using Jupiter-U filter (approx. 280-385nm, effective peak approx. 365nm):
 

Transmission graph:
 


This comparison shows, that the Kuri 35mm is hard to beat, but the Cassaron does quite well for a simple triplet lens, especially reaching quite deep into UV when the Jupiter-U filter is being used. It has 1.9% focus shift, compared to 1.0% the Kuri 35mm has. A quite useful lens and maybe even easier to find than the Kuri.


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] whitebalancing using a 35mm wide angle lens for UV

Today I made some experiments using wide(r) angle lenses for shooting reflected UV using my UV sensitive camera.

I had previously written about proper whitebalancing to reach a standardized false color UV palette using a true apochromatically corrected UV lens and also about doing that for other wide angle lenses. Now I wanted to reach about the same "colors" using such a lens which transmits much less UV, in that case here a 35mm c-mount lens.

[click on images to see larger ones]

Standardized reflected false UV "colors" according to the previously described "UV color palette" related to wavelength.

The normal and high intensity palette:



The reflected UV images show a Rudbeckia hirta flower. Left the result before applying my whitebalancing procedure; on teh right after whitebalancing using my ReflectionDisc (and some special in-camera tweaking):

[the colors on the left image are NOT according to the standardized palette!]

Well, as you can see, about the same colors could be reached on the right image, still a little different, as some parts of the spectrum are missing (the shorter wave UV-A sub-bands more specifically, so there is no green as that lens only transmits to about 350nm). Still it gets evident that this Rudbeckia flower has a UV reflection from its petal tips of around 360nm.

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