Spring Flowers 2014: Scilla - 80mm Quartz Fluorite lens for reflected ultraviolet photography

Well, spring finally seem to have arrived in Weinheim where I live, so here a few shots of some first spring flowers, like that yet unidentified Scilla sp.. Shots were done aside from visible photography in reflected ultraviolet using Baader-U filter and in simulated bee vision using my XBV6 filter. Lens used was an older f3.2 / 80mm Quartz Fluorite lens. Light source was sun. All shots were done at approx. 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):  

Simulated bee vision image using experimental XBV filter:  


This attractive early spring flower shows its not very prominent UV pattern. Scilla usually is reflecting only in long wave UV around 380nm, visible as a light bluish violet and its center (anthers, stamen) is darker in UV. This older quartz fluorite lens is reproducing this quite well and all that gets nicely visible.


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

Spring Flowers 2014: Scilla bifolia - 80mm Quartz Fluorite lens for reflected ultraviolet photography

Well, spring finally seem to have arrived in Weinheim where I live, so here a few shots of some first spring flowers, like that Scilla bifolia. Shots were done aside from visible photography in reflected ultraviolet using Baader-U filter and in simulated bee vision using my XBV6 filter. Lens used was an older f3.2 / 80mm Quartz Fluorite lens. Light source was sun. All shots were done at approx. 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):  

Simulated bee vision image using experimental XBV filter:  


This attractive early spring flower shows its not very prominent UV pattern. Scilla usually is reflecting only in long wave UV around 380nm, visible as a bluish violet and its center (anthers, stamen) is darker than the tips in UV, excatly the other way round than it appears to us in human vision. This older quartz fluorite lens is reproducing this quite well and all that gets nicely visible.


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

Spring Flowers 2014: Crocus longiflorus - 80mm Quartz Fluorite lens for reflected ultraviolet photography

Well, spring finally seem to have arrived in Weinheim where I live, so here a few shots of some first spring flowers, like that Crocus longiflorus. Shots were done aside from visible photography in reflected ultraviolet using Baader-U filter and in simulated bee vision using my XBV6 filter. Lens used was an older f3.2 / 80mm Quartz Fluorite lens. Light source was sun. All shots were done at approx. 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):  

Simulated bee vision image using experimental XBV filter:  


This attractive early spring flower shows its very specific UV pattern. Crocus usually is reflecting only in long wave UV around 380nm, visible as a bluish violet and its center (anthers, stamen) is UV dark. Its petals inside the flower are UV reflective, maybe caused by the shiny petal surface. This older quartz fluorite lens is reproducing this quite well and all that gets nicely visible.

P.S.: UV photographgy can reveal if a crocus is alive or dead, have a look HERE.

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

[UV] Old Achromatic Quartz Fluorite Lens for Ultraviolet Photography (VII)

This is the time of the year where usually (new) equipment is tested or modified, and being prepared for the forthcoming "UV shooting season". And so today I would like to show more about that quartz fluorite lens from an older spectrometer system I have previously written about a few times.
Today now shots of a decorative winter flower Winter Jasmine - Jasminum nudiflorum in reflected ultraviolet using Baader-U filter (approx. 320-395nm, peak approx. 350nm) as a test target. Lenses used were that adapted and modified f3.2 / 80mm (approx.) Quartz Fluorite Lens system (QF), as well as my CERCO f4.1 / 94mm lens for reference. Light source was a modified Xenon flash. All shots were done at approximately f8 and the difference in focal length has been compensated by adjusting the distance lens - flower. The UV images where whitebalanced using my preset for the CERCO lens to allow for a reliable comparison.

[click on image to see a larger one]

UV image using Baader-U filter and CERCO lens:  

UV image using Baader-U filter and QF lens:  

Diptych of the above images (QF left, Cerco right):  

Diptych of the above images (QF left, Cerco right) - details:  

Measured spectral transmission of that f3.2 / 80mm Quartz Fluorite Lens system (uncoated obviously):  


Both lenses seem to reproduce the specific reflected UV pattern of that Winter Jasmine quite well, and as expected my Cerco lens has an edge over that older Quartz Flourite lens. The QF is about 0.7 stops slower compared to the Cerco, to achieve about the same sharpness level, but the QF overall does quite well for such type of UV photography. So it is one of the very few known lenses which are able to break the 300nm transmission barrier, as even the best suitable lenses for UV I found in years of search (non quartz fluorite ones) stop transmitting around 320nm.

(I have re-evaluted the focal length of the quartz fluorite lens system (QF) and it is about f=80mm and its speed is about f3.2. It seems that the useful aperture settings for this lens are around f8 - f11 to achieve suitably sharp images.)

More about that used quartz fluorite lens is  HERE.

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

Winter Jasmine - Jasminum nudiflorum in reflected ultraviolet photography and simulated bee vision III

Today even more shots of a decorative winter flower Winter Jasmine - Jasminum nudiflorum in reflected ultraviolet using Baader-U filter and in simulated bee vision using my XBV6 filter. Lens used was an older fast cine lens lens. Light source was Xenon flash. All shots were done at f8. This time the UV image was individually whitebalanced.

[click on image to see a larger one]

Visible light image:  

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

Simulated bee vision image using experimental XBV filter:  

Triptych of the above images:  


This attractive winter flower shows its very specific UV pattern. Its center is UV dark, but its petals are strong UV reflective around 365nm, ie. UV bright, both invisible to us humans. Also this older cine lens is reproducing this quite well and all that gets nicely visible, here now matched to the CERCO quartz fluorite lens results.


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

Winter Jasmine - Jasminum nudiflorum in reflected ultraviolet photography and simulated bee vision II

Today more shots of a decorative winter flower Winter Jasmine - Jasminum nudiflorum in reflected ultraviolet using Baader-U filter and in simulated bee vision using my XBV6 filter. Lens used was an older fast 75mm cine lens lens. Light source was Xenon flash. All shots were done at 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):  

Simulated bee vision image using experimental XBV filter:  

Triptych of the above images:  


This attractive winter flower shows its very specific UV pattern. Its center is UV dark, but its petals are strong UV reflective around 365nm, ie. UV bright, both invisible to us humans. Also this older cine lens is reproducing this quite well and all that gets nicely visible.


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

Winter Jasmine - Jasminum nudiflorum in reflected ultraviolet photography and simulated bee vision

Today shots of a decorative winter flower Winter Jasmine - Jasminum nudiflorum in reflected ultraviolet using Baader-U filter and in simulated bee vision using my XBV6 filter. Lens used was the CERCO 94mm quartz fluorite lens. Light source was Xenon flash. All shots were done at 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):  

Simulated bee vision image using experimental XBV filter:  

Triptych of the above images:  


This attractive winter flower shows its very specific UV pattern. Its center is UV dark, but its petals are strong UV reflective around 365nm, ie. UV bright, both invisible to us humans and all that gets nicely visible.


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