Human UV vision simulated using reflected ultraviolet UV photography II

Today more about Human UV vision still using shots of that decorative flower, a Zinnia haageana - Mexican Zinnia in reflected ultraviolet photography using my "work horse" UV filter, the Baader-U filter but additionally a new, very special XHUV filter to visualize and simulate HUMAN UV vision (hence labeled XHUV). I had mentioned before that it has been reported since years, that some humans have UV vision, mostly either after cataract surgery where the natural lens was replaced by one that allows UV to be transmitted or because of having aphakia. The ongoing discussion with individuals having this ability led me to do some more tests on myself and it seems that I also have some (limited) ability to see UV light, well not much, and quite blurry it was, but nevertheless it seems to be there (compared to my wife who cannot see anything at all under identical test conditions). Using my UV sensitive camera I tried to replicate the colors I am able to see as follows. But now I added an UV transmitting calcium fluoride diopter lens with 2 diotries (f=500mm) and the image is not blurry anymore but sharply focused.

*** DO NOT TRY TO REPLICATE THAT HERE, if you don't know exactly what you are doing, as it may harm your eyesight!! ***

Let me explain what I did a bit further: First one starts looking in the visible at the flower (and taking a normal photograph to document that for comparison reasons), then a UV transmitting filter stacked with that mentioned UV transmitting diopter lens is held in front of one eye, shielding all the natural light around. Let the eye adapt to darkness and then UV image starts to form. I use an UV LED to enhance the then visible UV image. Then I attach to my UV sensitive camera an UV transmitting filter and record in similar fashion what I have seen. Use these two images side-e-side as a diyptych to present the differences - this is what I have done here. It is a comparison side-a-side, is is NOT concurrently seen. What I have additionally done is experiment with various UV transmitting filters until I found one that closely records what I have seen in UV, that's the now called XHUV filter. Plus I added an UV transmitting calcium fluoride diopter lens and the UV image is then sharply focused.

Lens was a Hamamatsu 50mm quartz fluorite lens. Light source for photography was a UV enhanced Xenon flash, for the human tests sun and a UV LED. All photographic shots were done at about f8.

[click on image to see a larger one]

Visible light image, identical to how I see it (only for comparison):  

UV image using XHUV filter as my camera sees it, simulating how I saw it before (including the blurriness as I could not get sharp UV focus):  

UV image using XHUV filter as my camera sees it, simulating how I see it now (including that calcium fluoride diopter lens, now yielding sharp UV focus):  

Diptych to compare camera simulated human UV image before (left) and after (right) calcium fluoride diopter use:
 


Mexican Zinnia flowers have a very specific UV pattern, its petal tips are very UV bright and teh center is quite dark. Hence why I used that to test out what I am able to see looking through an UV transmitting filter and then simulate that using my UV sensitive camera using the XHUV filter. I hope all this gets nicely visible.

*** Again: DO NOT TRY TO REPLICATE THAT HERE, if you don't know exactly what you are doing, as it may harm your eyesight!! ***

I have written previously about this 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

Human UV vision simulated using reflected ultraviolet UV photography

Today about something very different, still using shots of a decorative flower, a Zinnia haageana - Mexican Zinnia in reflected ultraviolet photography using my "work horse" UV filter, the Baader-U filter but additionally a new, very special XHUV filter, this time NOT for simulating bee and butterfly vision, but to visualize and simulate HUMAN UV vision (hence labeled XHUV). It has been reported since years, that some humans have UV vision, mostly either after cataract surgery where the natural lens was replaced by one that allows UV to be transmitted or because of having aphakia. Some individuals having UV vision are known to me and I am in discussion with them about this ability. This discussion led me to do some tests on myself and it seems that I also have some (limited) ability to see UV light, well not much, and quite blurry, but nevertheless it seems to be there (compared to my wife who cannot see anything at all under identical test conditions). Using my UV sensitive camera I tried to simulate the colors I am able to see as follows using XHUV filter.

*** DO NOT TRY TO REPLICATE THAT HERE, if you don't know exactly what you are doing, as it may harm your eyesight!! ***

Let me explain it a bit further: First one starts looking in the visible at the flower (and taking a normal photograph to document that for comparison reasons), then an UV transmitting filter is held in front of one eye, shielding all the natural light around. Let the eye adapt to darkness and then UV image starts to form. Use a UV LED to enhance that if needed. Then attach to the UV sensitive camera an UV transmitting filter and record in similar fashion when has been seen. Use these two images side-e-side as a diyptych to present the differences in visible and UV vision - this is what I have done here. It is a comparison side-a-side, is is NOT concurrently seen. What I have additionally done is experiment with various UV transmitting filters until I found one that closely simulates what I have seen in UV, that's the now called XHUV filter.

Lens was a Hamamatsu 50mm quartz fluorite lens. Light source for photography was a UV enhanced Xenon flash, for the human tests sun and a UV LED. All photographic shots were done at about f8.

[click on image to see a larger one]

Visible light image, identical to how I see it:  

UV image using Baader-U filter (approx. 320-395nm, effective peak approx. 375nm) as my UV camera sees it:  

UV image using XHUV filter as my camera sees it, quite similar to how I see it (including the blurriness as I cannot get sharp UV focus):  

Diptych to compare visible image with camera UV image:
 

Diptych to compare visible image with camera simulated human UV image:
 

Diptych to compare camera UV image with camera simulated human UV image:
 


Mexican Zinnia flowers have a very specific UV pattern, its petals are very UV dark on the middle and bottom, but its petal tips are very UV bright. Hence why I used that to test out what I would be able to see looking through a UV transmitting filter and then to simulate that using my UV sensitive camera. I hope all this gets nicely visible.

*** Again: DO NOT TRY TO REPLICATE THAT HERE, if you don't know exactly what you are doing, as it may harm your eyesight!! ***

There is a follow up about Human UV vision 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

Mexican Zinnia - Zinnia haageana in reflected ultraviolet photography at 337nm, simulated butterfly and bee vision VII

Today different shots of a decorative flower, a Zinnia haageana - Mexican Zinnia in reflected ultraviolet photography using my "work horse" UV filter, the Baader-U and Jupiter-U filter as well as my XBV filters for simulating bee and butterfly vision. Lens was a Hamamatsu 50mm lens. Light source was Xenon flash. All shots were done at about f8.

[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):  

UV image using special 337nm filter (approx. 310 - 345nm, peak approx. 337nm):  

Simulated butterfly vision (UV - VIS) using XBV3 filter:  

Simulated bee vision (UV - VIS) using XBV6 filter:  

Simulated bee vision (UV - VIS) using XBV5 filter:  

Quadriptych of some of the above:
 


Mexican Zinnia flowers have a very specific UV pattern, its petals are very UV dark on the middle and bottom, but its petal tips are very UV bright, reaching much deeper into UV as any other flower I know (<345nm), and all this gets nicely visible.


I have written previously about these flowers 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

50mm Hamamatsu Quartz fluorite lens vs D.O. Industries enlarger lens for reflected UV photography II

Today again about comparing a quartz fluorite lens with a conventional, but UV capable D.O. Industries enlarger lens. I have done a similar comparison previously here. I'm using a beautiful yellow/red Phalaenopsis flower, for that as well as my "work horse" UV filter, the Baader-U filter. Lenses used are a Hamamatsu f3.5/50mm quartz fluorite lens as well as a 4.5/50mm D.O. Industries enlarger lens. Light source was an UV enhanced Xenon flash. All shots done at f8.

[click on image to see a larger one]

Visible light image for comparison:
 

1) Quartz Fluorite lens: "standard" UV image using Baader-U filter:
 

2) Enlarger lens: "standard" UV image using Baader-U filter:
 

UV - VIS differential:
 

It gets pretty obvious that this very affordable D.O. Industries enlarger lens reaches quite close to the quartz fluorite lens, yet can't quite beat it in terms of sharpness + contrast. But it is astonishingly close. Also its focus shift is relatively small, as the differential image clearly shows. Quite a nice lens!

I have written about that enlarger lens before 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

Eucharis grandiflora: UV induced fluorescence and reflected colorful UV photography II

This is again about: Eucharis × grandiflora, also called Amazon Lily this time using my "work horse" UV filter, the Baader-U filter and a Hamamatsu f3.5/50mm quartz fluorite lens. Light source was an UV enhanced Xenon flash and a Nichia UV torch for the UV induced stimulated visible fluorescence (UVIVF) shot.

[click on image to see a larger one]

visible light image:
 

"standard" UV image using Baader-U filter:
 

UV stimulated visible fluorescence using UV/IR blocking filter:
 

UV stimulated visible fluorescence using different UV/IR blocking filter:
 

Also here not much prominently visible UV pattern, except that the base of the flower, where usually nectar can be found, lights up, as well as its pollen does.

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

Hamamatsu A4869 UV lens f3.5/50mm for reflected UV photography

I got a loaner lens for testing, a Hamamatsu f3.5/50mm UV lens, made of quartz and fluorite, a 5e/5g design, with obviously uncoated lens elements (which might be the reason for the prominent hotspot that it shows in VIS and UV), as this is some 15-20 year old lens I have been told. It has a c-mount and was made for Hamamatsu's line of high sensitive and intensified UV cameras, hence its image circle is just 16mm as per its specs. I measured the latter and the real image circle is larger (certainly not as well defined), about 25-27mm, so it will not cover APS-C sensors, that require at least 30.1mm.

[click on image to see a larger one]

 First thing tested was vignetting, which it shows quite some wide open, if used with a 21mm image sensor.

Vignetting, fully open on a 21mm diameter imager:


Well, I was curious to see how it would perform in VIS and UV, so I took a few shots with it, using for UV my "work horse" UV filter, the Baader-U. This lens has a common 40.5mm filter thread, so mounting filters was easy, just a step ring was needed. Unfortunately the lens front rotates while focusing as do many other lenses. I used sunlight for the outside shots and Xenon flashlights for the studio macro shots, using a Rudbeckia fulgida flower as a target.

Outside shot, VIS, fully open:


Outside shot, UV, fully open:


Outside shot, VIS, stopped down to f8:
 

Outside shot, UV, stopped down to f8:
 

Stopping down significantly reduces blurriness that is visible wide open even in the image center as well as some curvature of field and enhances imaged sharpness considerably.

It gets quite obvious, that stopping down the lens (from about f8 onwards) makes visible a quite prominent hotspot that is has in VIS + UV in certain lighting situations:

Outside shot, VIS, stopped down to f11, central hotspot:
 

Outside shot, UV, stopped down to f11, central hotspot:
 


Now on to studio macro shots...

Macro shot, UV, stopped down to f11:
 

Macro shot, UV, stopped down to f11, detail :
 
The detail shows some strange artifacts which could either result from the flower being wet or lacking lens resolution. More research needs to be done on that.

Here is its transmission graph versus some normal and quartz fluorite reference lenses:

 
[Be reminded that this measuring setup used is valid to about 310-320nm onwards, so both quartz fluorite lenses transmit UV better than shown]

To summarize, this (rather expensive $$$$) Hamamatsu A4869 f3.5/50mm UV lens is certainly not a bad lens. That prominent hotspot it has needs carefully controlled lighting situations to avoid spoiled images, which in the field outside cannot be secured, so it's "hit and miss" unfortunately. So I would rather recommend it for studio work only. Also the lens needs to be stopped down to at least f8 to achieve a flat field and sufficient sharpness. In studio the lens performs much better, as my examples show and a thin c-mount extension ring added gives the needed close up/macro focusing distance, that this lens otherwise not has (closest focusing is 0.6 meters, 2ft). Infinity focus was perfectly adjusted and no re-collimation was needed.

P.S.: It has been confirmed by Hamamatsu staff that this lens is about 15 years old and was designed to match the needs of maximum 2-3 Mpix cameras. Hence the limited resolution and most likely the artifacts are diffraction effects. Further it was mentioned to me that the found hotspot may be the result of uncoated lens elements being used, so stray and reflected light bounces between them and the shiny sensor surface.

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