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

Today in 2020 some first outdoor shots of that long blooming flower, a 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 with some Nichia 365nm UV-LED support.

[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

Reflected UV photography in polarized light X - Gazania

Today more about UV polarizer experiments, using a special UV capable circular polarizer in front of my multispectral camera and UV-Nikkor 105mm lens, for recording polarized reflected UV images. Flower here was a long blooming, perennial flower Gazania . UV filter used was my classic Baader-U filter; sun was used as light source.

[click on image gets you a larger image]

Here photographic results I got (took multiple images while rotating the filter), presented as animated gif....

Gazania flower through a rotating circular polarizer in A-mode i.e. exposure compensated...

Reflected UV light - Sunlight:

This flower shows some interesting changes in the polarization angle especially on its anters.  Bees have sensors on the outer ring of their compound eyes which are able to detect polarized light, so that might give this flower an advantage.

Reflected UV photography in polarized light shows quite some usefulness, especially if there are (glossy) surfaces which change the polarization angle of light and which the polarizer filter makes visible. Downside is that one needs about 2 stops more exposure, due to the low approx. 25% transmission.

Some insects are able to see the polarization angle (and btw. we humans can also, but needs some traing: Haidinger's Brush) especially honeybees which navigate using the polarization angle of ultraviolet (UV) light.

I have written more about using UV polarizers HERE

I have written more about that Gazania 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