EADS SODERN CERCO f4.1 94mm vs Coastal Optical Systems Inc. 105mm f/4 UV-Micro-Apo lens for reflected ultraviolet photography

Today about two specialized UV lenses, the EADS SODERN CERCO type 2085 f4.1 94mm and the Coastal Optical Systems Inc. (COSI) 105mm f/4 UV-Micro-Apo apochromatic quartz fluorite lenses. In lack of a flower with UV pattern, I'm using a African violet hybride flower for that test as well as my "work horse" UV filter, the Baader-U filter. Light source was Xenon light. All shots were done at f5.6.

[click on image to see a larger one]

Diptych image CERCO 94mm (left) vs COSI 105mm lens (right), Visual light:
 

Diptych image CERCO 94mm (left) vs COSI 105mm lens (right), reflected UV using Baader-U filter (approx. 320-395nm, peak approx. 350nm):
 

Diptych detail image CERCO 94mm (left) vs COSI 105mm lens (right), reflected UV using Baader-U filter (approx. 320-395nm, peak approx. 350nm):
 

The comparison images clearly show that both lenses work exceptionally well for reflected UV as for visual photography and deliver sharp images rich in contrast and detail. I had to adjust the camera position to equalize the focal length differences, so this is not a scientific lens test, but the view of a user. Both come in Nikon-F mount, but the COSI lens covers full format sensors, the CERCO only about the smaller APS-C format (25mm image diameter).

P.S.: The images were not re-adjusted in focus between UV and VIS shots, to show that there is no focus shift between VIS and UV.

P.P.S.: those images accidentially work as 3D crosseye stereo images...

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 deep reflected ultraviolet photography, simulated butterfly and bee vision V

Today more about my last surviving Gazania flower Treasury flower - Gazania rigens in reflected ultraviolet photography using my "work horse" UV filter, the Baader-U filter as well as my XBV filters for simulating bee and butterfly vision. Lens used was the 94mm CERCO quartz fluorite lens. Light source was a modified for UV high power Xenon flash.

[click on image to see a larger one]

Visible light image using UV/IR cut filter:
 

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

Simulated butterfly vision (UV - VIS) using XBV4 filter:
 

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

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

Infrared light image using IR filter:
 

Quadriptych of some of the above:
 


Interesting to notice also here, how the visible details change when the used wavelength gets shorter and the then appearance of unique colors when the butterfly and bee vision filters are applied. The outer petals reflect strongly UV around 370nm, there are also highly reflecting marks inside around a dark UV center and all that gets nicely visible, which I have also previously shown.

There is a Part IV about this same flower using filter stacks HERE.
There is a Part VI about this 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

Treasury flower - Gazania rigens in deep reflected ultraviolet photography, simulated butterfly and bee vision IV

Today about my last surviving Gazania flower Treasury flower - Gazania rigens in reflected ultraviolet photography using my "work horse" UV filter, the Baader-U filter as well as my XBV filters for simulating bee and butterfly vision, but this time additionally also the Jupiter-U (280-385nm, eff. 365nm) and Saturn-U (300-350nm, eff. 325nm) filters. Lens used was the 94mm CERCO quartz fluorite lens. Light source was a modified for UV high power Xenon flash.

[click on image to see a larger one]

Visible light image using UV/IR cut filter:
 

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 Saturn-U filter (approx. 300-350nm, effective peak approx. 325nm):
 

UV image using Deep UV filter (approx.300 - 315nm, effective peak approx. 308nm):
 

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

Polyptych of the above:
 


Interesting to notice, how the visible details change when the used wavelength gets shorter and the then appearance of unique colors. The outer petals reflect strongly UV around 370nm, there are also highly reflecting marks inside around a dark UV center and all that gets nicely visible, which I have also previously shown.

There is a Part III about this same flower using filter stacks 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

Old 105mm + 75mm Helioplan enlarger lenses for reflected ultraviolet photography

Today about some older, quite capable UV transmitting Helioplan enlarger lenses. I'm using a Gazania rigens flower for that test as well as my "work horse" UV filter, the Baader-U filter. Lenses used were older 75mm and 105mm Helioplan enlarger lenses of dialyte construction. Light source was Xenon light. All shots were done at f11.

[click on image to see a larger one]

Diptych image using 75mm lens, Visual and reflected UV using Baader-U filter (approx. 320-395nm, peak approx. 350nm):
 

Diptych image using 105mm lens, Visual and reflected UV using Baader-U filter (approx. 320-395nm, peak approx. 350nm):
 

Diptych image 75mm vs. 105mm lens, both reflected UV using Baader-U filter:
 

The comparison images clearly show that the 75mm has an edge over the 105mm lens in terms of UV tramsission, but also in terms of sharpness. Both lenses are nevertheless quite capable, despite their 50++ years of age.

P.S.: The visual images were not re-adjusted in focus, to show the small focus shift between VIS and UV.

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

Orange coneflower - Rudbeckia fulgida in reflected ultraviolet photography and simulated bee vision VIII

Today more shots of that decorative flower Orange coneflower - Rudbeckia fulgida in reflected ultraviolet using Baader-U filter and in simulated bee vision using my XBV6 filter. Lens used was the now well known Novoflex Noflexar f3.5/35mm 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 flower shows its very specific UV pattern, its petals have an UV dark pattern, invisible to us humans. This lens is a well known performer, also in UV and transmits up to approx. 330nm, is quite sharp and has virtually no focus shift, quite enough to make the UV pattern clearly visible.

I have previously written about this lens HERE and about that R. fulgida flower HERE.

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

Using sunlight or shadow in reflected ultraviolet photography

Today shots of a R. fulgida flower, but is about some principle observations when doing reflected ultraviolet photography in sun or shadow. I was using my "work horse" UV filter, the Baader-U filter. Lens was my CERCO 94mm quartz flourite lens. Light source was sunlight resp. shadow / blue sky at around 1800 hours (early evening). All shots were done at about f5.6.

[click on image to see a larger one]

Visible light image - Sunlight  

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

Visible light image - Shadow  

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

Quadriptych of the above images for comparison:  

Quadriptych of the above images for comparison (detail):  


I had the rare chance to find about identically looking R. fulgida flowers just a few centimeters apart, one in sunlight and one in shadow, when I noticed how different the UV results looked like. Comparing the images taken in sunlight or in shadow (blue sky being the only UV source), the latter UV image shows much clearer details and more even exposure. It comes at a steep difference however, 2.5EV (stops) more the shadow image took.


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

Autumn crocus - Colchicum autumnale in reflected ultraviolet photography and simulated bee vision

Today shots of a decorative flower, Autumn crocus - Colchicum autumnale in reflected ultraviolet photography using my "work horse" UV filter, the Baader-U filter as well as in simulated bee vision using my XBV6 filter. Lens was my CERCO 94mm quartz flourite lens. Light source was sunlight. All shots were done at about f5.6.

[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:  


Colchicum flowers have no specific UV pattern, reflect hardly any UV, but still are able to see them in blue and green, and this gets nicely visible.


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

Black Cohosh - Cimicifuga racemosa in reflected ultraviolet photography and simulated bee vision

Today shots of a decorative flower, Black Cohosh - Cimicifuga racemosa in reflected ultraviolet photography using my "work horse" UV filter, the Baader-U filter as well as in simulated bee vision using my XBV6 filter. Lens was my CERCO 94mm quartz flourite lens. Light source was sunlight. All shots were done at about f5.6.

[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:  


Cimicifuga flowers (inflorescence) have no very specific UV pattern, but reflect UV brightly around 380nm, and this gets nicely visible.


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

Mexican Zinnia - Zinnia haagenea in reflected ultraviolet photography and simulated bee vision XVI

Today more shots of a different type of that decorative flower, Mexican Zinnia - Zinnia haagenea in reflected ultraviolet photography using my "work horse" UV filter, the Baader-U filter as well as in simulated bee vision using my XBV6 filter. Lens was my CERCO 94mm quartz flourite lens. Light source was sunlight. All shots were done at about f5.6. I have previously written about those Zinnias HERE.

[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:  


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


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

Three-leaved Coneflower - Rudbeckia triloba and Zinnia in reflected ultraviolet photography and simulated bee vision III

Here comparative shots of that decorative Three-leaved Coneflower - Rudbeckia triloba and a red Zinnia flower in reflected ultraviolet using Baader-U filter and in simulated bee vision using my XBV6 filter. Lens was my CERCO 94mm quartz flourite lens. Light source was sunlight. All shots were done at about f5.6.

[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 R. triloba flower has a very specific UV pattern, its petals are bright on the petal tips (reflecting around 365nm), have a UV dark bullseye pattern invisible to us humans and also the flower center is quite UV dark. Compared to that that bright red Zinnia flower (to us humans), looks rather dull and dark in UV, except some central parts, so all this gets nicely visible.

I have previously written about that flower HERE.

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

Orange coneflower - Rudbeckia fulgida and Mexican Zinna - Zinnia haageana in reflected ultraviolet photography and simulated bee vision

Today more shots of these decorative flowers Orange coneflower - Rudbeckia fulgida var deamii and Mexican Zinnia - Zinnia haageana in reflected ultraviolet using Baader-U filter and in simulated bee + butterfly vision using my experimental XBV3 and XBV6 filters. Lens was my CERCO 94mm quartz flourite 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 butterfly vision image using experimental XBV3 filter:  

Simulated bee vision image using experimental XBV6 filter:  

Quadriptych of the above images:  


These attractive flower show very specific UV patterns, their petals have an UV dark pattern middle to base with UV bright petal tips, Zinnia reflecting around 340nm, Rudbeckia around 360nm, both invisible to us humans. All this gets nicely visible.

I have previously written about these flowers HERE and HERE.

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