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

Today more macro shots of that decorative flower Orange coneflower - Rudbeckia fulgida var deamii in reflected ultraviolet using Baader-U filter and in simulated bee vision using my XBV6 filter. Lens used was an older 2.8/55mm triplet taking lens. Light source was Xenon flash. All shots were done at about f11.

[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. It also shows that in UV and BV damages on petals shows easier and earlier, and all this gets nicely visible. The lens being a "normal" taking lens, it transmits less UV than a capable UV lens like the Dialyte lenses used previously, yet enough to make the UV pattern visible.

I have previously written about this flower HERE.

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

Three 40mm lenses for reflected UV photography

Today about a comparison of three lenses of 40mm focal length for reflected UV, one a Cooke Triplet (C40), one a Dialyte design (D40), one a complex Sonnar design (S40) whose makers will be revealed here later - or simply contact me about it. The best of the three will also compared against the Kuribayashi 35mm. I'm using a yellow/red Phalaenopsis flower for that and my "work horse" UV filter, the Baader-U filter. Light source was an UV enhanced Xenon flash. All shots were done at f8 and are presented in a side-a-side format for easier comparison.

[click on image to see a larger one]

UV image using the Baader-U filter (approx. 320-395nm, effective peak approx. 375nm) - Cooke left, Dialyte middle, Sonnar right:
 

Here the three contestants present themselves side-a-side: It gets obvious, that the Sonnar is the softest of the three and has a bit less UV transmission (the latter had to be expected). The Cooke triplet lens and especially the Dialyte however show some respectable sharpness. So lets's have a closer look at the latter two.

UV image using the Baader-U filter - Cooke left, Dialyte right:
 

Here, the Dialyte has an edge over the Triplet, quite higher micro-contrast and higher detail reproduction, quite remarkable, considering it is an old prewar lens, and uncoated. So let's see how that Dialyte performs against the Kuribayashi 35mm.

UV image using the Baader-U filter - Dialyte lft, Kuribayashi 35mm right:
 

Here now it is hard to choose a winner, as both have very high sharpness and contrast, quite remarkable considering their age difference. I'm undicided honestly.

Transmission graph:
 

The Triplet is represented by a yellow line, the Dialyte by a reddish brown line, the Sonnar by a blue line and finally the Kuribayashi by a pink line. Transmisson of all lenses is quite high, at 365nm Sonnar: 60%, Dialyte: 64%, Triplet: 70% and finally the Kuribayashi 77%. Their reach into UV is quite remarkable, the Kuribayashi and Dialyte having the deepest, Triplet surprisingly the least, maybe caused by its bluish coating. So overall, some remarkable lenses for reflected 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