Wednesday, March 10, 2021

Oncostele Wildcat 'Golden Red Star' in visible, reflected UV, simulated bee and butterfly vision using a Jenoptik CoastalOpt® UV-VIS-IR 60 mm 1:4 APO Macro lens III

Today in March 2021 more shots of an Orchid hybride, Oncostele Wildcat 'Golden Red Star' in reflected ultraviolet photography as well as simulated bee and butterfly vision - but with a quite different lens, the Jenoptik CoastalOpt® UV-VIS-IR 60 mm 1:4 APO Macro quartz fluorite lens, which is on the scientific lens market for a few years now. UV filter used was the Baader-U filter, my "work horse" filter for reflected UV as well as my proprietary XBV filters for simulated bee and butterfly vision. All shots were done at f8. Light source used was a modified for high UV output Xenon flash. I have additionally used a 365nm UV LED for better focusing, (which unfortunately has influenced the white balance somewhat, in case you wonder).

[click on image to see a larger one]

Human Vision (VIS):

Reflected UV (Baader-U):

Simulated Butterfly Vision:

Simulated Bee Vision:

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

This orchid has a very specific UV pattern, its petals are very UV dark, but its lower petal lip shows on the lower center a very UV bright spot which gets nicely visible.

This 60mm lens is a rather well working one, with a nice close up focus capability from infinity up to 26cm (0.26 meter). Sharpness is quite good and so is its contrast, even wide open. It has a transmission waveband of 290nm - 1500nm and is apochromatic from 315nm - 1100nm. It is had an advanced broadband BBAR coating which increases transmission considerably and reduced flares; my measured transmission spectra of it may be seen here. It has a standard Nikon-F mount, and covers full format sensors (41mm diagonal). There have been reports of a UV hotspot, but the solution to it has been found by using a tight sunshade.

I have written more about this orchid HERE

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

More info on this very interesting field may be found on my site