Saturday, July 8, 2017

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

Today detail shots of a cultivar 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 vision using my XBV filter. All shots were done at f8. Lens was a UV-Nikkor 105mm quartz fluorite lens. Light source was sunlight.

[click on image to see a larger one]

Human vision:
 

Reflected UV:
 

Simulated bee vision:
 

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

This flower shows a very prominent UV bullseye pattern, as its petals are very UV bright (around 365nm) to about the middle and its center is very UV dark, and all this gets nicely visible also in simulated bee 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

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

Today shots of a cultivar 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 vision using my XBV filter. All shots were done at f8. Lens was a UV-Nikkor 105mm quartz fluorite lens. Light source was sunlight.

[click on image to see a larger one]

Human vision:
 

Reflected UV:
 

Simulated bee vision:
 

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

This flower shows a very prominent UV bullseye pattern, as its petals are very UV bright (around 365nm) to about the middle and its center is very UV dark, and all this gets nicely visible also in simulated bee 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

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

Today shots of a current, long blooming flower, a yellowish white variant of a Treasury flower - Gazania rigens in reflected ultraviolet photography and 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, background was the flower's own foliage.

[click on image to see a larger one]

Human vision:
 

Reflected UV:
 

Simulated bee vision:
 

Simulated butterfly vision:
 

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

This Gazania's outer petals reflect strongly UV around 372nm, wheras the inner parts are much darker hence forming UV nectar guides for bees. There are also highly UV reflecting marks inside around a dark UV center, all invisible to us humans but clearly visible to bees, and all this gets nicely visible here, also in simulated bee 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

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

Today shots of a current, long blooming flower, an all yellow variant of a Treasury flower - Gazania rigens in reflected ultraviolet photography and simulated bee 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 vision. Lens was a UV-Nikkor 105mm quartz fluorite lens. Light source was sunlight, background was the flower's own foliage.

[click on image to see a larger one]

Human vision:
 

Reflected UV:
 

Simulated bee vision:
 

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

This Gazania's outer petals reflect strongly UV around 365nm, and there are also highly UV reflecting marks inside around a dark UV center, all invisible to us humans, but all this gets nicely visible, also in simulated bee vision.

I have written about 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

Saturday, July 1, 2017

UV-Nikkor 105mm vs Coastal Optical systems 105mm lens for reflected ultraviolet (UV) photography

Today about shooting with two dedicated UV lenses, the Coastal Optical Systems / Jenoptik UV-Micro-Apo f4 / 105mm and the classic UV lens, the UV-Nikkor f4.5 / 105mm in a non-scientific photographic comparision at shooting in reflected UV, using the Baader-U filter at natural light. Both lenses were used with a long 80mm sunshade, to avoid diminished contrast, which may happen if shot without.

[click on image to see a larger one]

reflected UV images taken at f4.5:


reflected UV images taken at f8:


The UV-Nikkor 105mm image is shown on the left side, the Coastal Optical Systems 105mm on the right side. First batch was shot at f4.5, second batch at f8. White balance was done for the UV-Nikkor 105mm.

The UV-Nikkor 105mm seems to have an edge over the Coastal Optics 105mm in terms of sharpness and contrast, especially when used fully open at f4.5, but stopped down to f8 the difference gets significantly smaller, as the Coastal gains quite a bit of sharpness and also contrast.

Both lenses require about the same white balance, due to their flat UV transmission (more about that later) and show about identical exposure, with exposure times having a slight nod towards the Coastal Optics lens (1/3 stop less), which in practice is insignificant.

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

Using a proper sunshade for best UV results using a Coastal Optical Systems / Jenoptik f4 / 105mm

Today about shooting with an UV lens (Coastal Optical Systems / Jenoptik UV-Micro-Apo f4 / 105mm) and considering how delicate those beasts can be to handle; here about using the right sunshade. Sounds rather boring actually, as we all rely on modern multicoated lenses and on my excursions I hardly ever see a photographer using his sunshade. But well, UV photography is a rather tricky subject anyway, and all aspects need consideration...

[click on image to see a larger one]





These are first normal visible light images, second reflected UV images and as one clearly sees here, using a sunshade (right side) can be rather critical, as the left image proves, showing very low contrast. In my case here, I used an 80mm deep shade for maximum effect, but w/o causing vignetting.

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