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UltravioletPhotography

Weeds


OlDoinyo

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This year has been a bumper one for weeds, what with an extended, cool, moist spring. A few have been particularly prominent. I am not the most accomplished at this kind of photography; my tripod is awkwardly tall for small specimens and swirling wind played havoc with my efforts; for the UV shots, it was necessary to shoot wide open at ISO 6400 to get a shutter speed short enough to capture anything at all, and focusing was by blind trial and error; so the images here are not presentation-quality. I have great respect for those who produce well-framed, tack-sharp images under such circumstances!

 

All images were taken with the Sony A900 and the Steinheil Cassar-S at maximum aperture, mounted on an extension tube. Visible images were obtained at ISO 100 or 400 through the Kolari deconverting filter. UV images were taken at ISO 6400 through the Baader U2 filter and display intent is BGR.

 

These first two are probably some sort of Asteraceae. They grow profusely on tall stems at the edge of paved areas. The first has lanceolate leaves, the second has fern-shaped ones:

 

post-66-0-71136400-1526442494.jpg

 

Both these have UV-dark centers. The first has strong short-wavelength absorption on the single ray flowers. The second is less interesting in UV: it has mild long-wavelength absorption on fused rays, which is common for many such blooms which are yellow in color.

 

This one is some kind of mint-thingy which rises out of a plantain-like whorl of foliage at the base:

 

post-66-0-12253200-1526442866.jpg

 

The flowers show moderate attenuation of short wavelengths. I don't know if this is biologically significant.

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The daisy like flower is an Erigeron species. These are often called Fleabanes. I suppose perhaps they were once useful for warding off that particular pest? I love the Fleabanes, so am enjoying seeing this one. They are sprightly and hardy. And have a nice sculptural quality in photographs, UV or otherwise. I can't guess at the species because there are quite a few in the US.

 

The BGR rendition is nice for the Erigeron. Now I want to go try that for some of my photos. It's cool looking.

 

I think your yellow flower might be some kind of Coreopsis. But again we have so very many yellow Asteraceae in the US.

 

And Mint-Thingy sounds right to me !!! I am terrible at ID-ing the mint family.

 

Don't worry about them being presentation quality. It's great to see the weeds from other locations besides my own. :)

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