Got a rare U.V. lens donated

Well, sometimes something really special happens! As I am into special optics and filters, as you may know by now, a member of some forum I am in informed me, that he found a special lens while cleaning up his house. He told me that it was labeled "U.V. Lens", so he thought of me and my UV and multispectral work and offered me that U.V. f4.3 lens with approx. 172mm focal length for just postage, which certainly was very kind of him!

So now on to the lens, which has a built in blue filter in its rear [these are not my images, but from the donating member here...]

U.V. Lens, pictures from the Donor

Now these are some quick test shots hand-holding filters in front of the lens: blue image is what seemingly it was made for (projecting images to a fluorescent screen I'm guessing), then I took that internal filter out and did an UV shot using a 365nm UV LED (quite sharp image) using the Baader-U filter and then a visible light image with suitable VIS-filter (which shows the lens was not computed for that) - all shot wide open at approx f4.

Here now the transmission of that lens: The RED line is the filter alone, the GREEN the lens alone, the BLUE as it came assembled with filter inside. Most likely it was designed to project images onto a fluorescent screen. That built in short pass filter makes me believe that. It is not really UV, but short wave blue, enough to stimulate visible fluorescence.

So it has to be seen what this lens can be used for, guess it will work well for reflected UV!

My thanks and well wishes go out to the donor!

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

Your optometrist may help to get special filters and lenses fitted

Well, sometimes I need special optics and filters as you may have seen already here. But often they need to be mounted into a frame or filter mount to fit my special lenses. Asking an optical company is often very expensive and they may not even be interested, as often it is just for single units. So what to do then? Ask your optometrist! I have a super good one here, who has always been very helpful, even cutting and precision grinding filter glass or diopter lenses into the special size I need!

My optometrist is https://flair-optik-gastell.de/ and I have always been very happy with him. He even proposed to use special UV cutting coatings on my glasses (>420nm transmitting only), as I work a lot with strong UV LED lights and since then no burning eyes anymore!

So when I do things like these, he was part of that, too...

Gazania Quadriptych of human vision, UV, simulated butterfly and bee vision (left to right, top to bottom):

 


Rudbeckia Quadriptych of human vision, ultraviolet, simulated bee and butterfly vision (left to right, top to bottom):
 

Ask your optometrist when you need something for your special photography work, he may be the one who has a solution, and often a much less expensive one!

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

Treasury flower - Gazania rigens in reflected ultraviolet photography and simulated bee and butterfly vision XXXVI

Today in Summer 2020 more outdoor shots of that long blooming orange-red Gazania flower, the Treasury flower - Gazania rigens shot in reflected ultraviolet photography, simulated bee and butterfly vision. All shots were done at f8 in reflected ultraviolet photography using my "work horse" UV filter, the Baader-U filter, as well as my XBV filters for simulated bee and butterfly vision. Lens was a UV-Nikkor 105mm quartz fluorite lens. Light source was sunlight (overcast).

[click on image to see a larger one]

Human vision:
 

Reflected UV:
 

Simulated butterfly vision:
 

Simulated bee vision:
 

Quadriptych of human vision, UV, simulated butterfly and bee vision (left to right, top to bottom):
 

This Gazania's outer petals strongly reflect UV around 365nm, whereas the inner petal parts are quite darker, hence forming UV nectar guides for UV seeing insects. There are also some highly UV reflecting marks inside around a dark UV center, all invisible to us humans, but clearly visible to bees and butterflies, and all this gets nicely visible here, also in simulated bee and butterfly vision.

I have written about this Gazania previously HERE
 
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

Black-eyed Susan - Rudbeckia hirta in reflected ultraviolet photography and simulated bee and butterfly vision XV

Today in 2020 shots of a beautiful flower, originating from the USA Prairie, a Black-eyed Susan - Rudbeckia hirta in reflected ultraviolet photography using my "work horse" UV filter, the Baader-U filter, as well as in simulated bee and butterfly vision using my XBV filters. All shots were done at f8. Lens was a UV-Nikkor 105mm quartz fluorite lens. Light source was sunlight (overcast).

[click on image to see a larger one]

Human vision:
 

Reflected ultraviolet (UV):
 

Simulated butterfly vision:
 

Simulated bee vision:
 

Quadriptych of human vision, ultraviolet, simulated bee and butterfly vision (left to right, top to bottom):
 

This flower shows a very prominent UV bullseye pattern, as its petal tips are very UV bright (around 365nm) and its center is very UV dark, and all this gets nicely visible, also in simulated bee and butterfly vision.

I have previously written about that flower HERE
 
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