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UltravioletPhotography

Lathyrus latifolius [Everlasting Vetchling]


Hornblende

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Hornblende

Viala, M. (2017) Lathyrus latifolius L. (Fabaceae) Everlasting Vetchling. Flowers photographed in visible, ultraviolet and infrared light.

http://www.ultraviol...ting-vetchling/

 

Montcalm-Tache Park, Gatineau, Quebec, Canada

3 July 2017

Wildflower

 

Other Common Names:

  • Broad-leaved everlasting pea
  • Everlasting pea
  • Pois vivace (french common name)

Comment:

All members of the pea family I came across so far were UV-dark. This species, however, is UV-reflective with darker veines.

This plant is non-native to North America

 

Reference:

1. New England Wild Flower Society (2017) Lathyrus latifolius L. Everlasting vetchling https://gobotany.new...rus/latifolius/

 

Equipement [Canon 6D full spectrum + EL-Nikkor 80mm f/5.6]

 

Visible Light:[f/16 for 1/400" @ISO400 in sunlight with Lifepixel UVIR-block filter - sunlight white balance preset]

post-136-0-02309100-1499126486.jpg

 

Ultraviolet Light: [f/5.6 for 1/50" @ISO6400 in sunlight with Baader UV-pass filter - white balance on white PTFE]

post-136-0-20737200-1499126481.jpg

 

Infrared light: [f/11 for 1/125" @ISO100 - in sunlight with Lifepixel IR830nm filter - monochrome image]

post-136-0-83889200-1499126482.jpg

 

Close-up in Ultraviolet Light: [same UV settings]

post-136-0-75036300-1499126688.jpg

 

 

[Published 3 July 2017]

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Andy Perrin
Nice pics! The whole pea family seems to have some very odd UV signatures. I don't think I've seen this much white in a UV photo before. I thought it was IR at first!
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Yes, the Fabaceae species can be pretty diverse in their UV signatures.

 

"White" or near "white" in a UV picture might mean the area is highly UV reflective. Or is pushed in processing to appear bright. However, as my own captures of this species also show the same "brightness", I think we can safely assume it is for real.

 

A lot of purple or blue flowers can be quite UV bright, by the way. The Campanula genus contains many examples of this.

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Hornblende

Thanks Andy! I think it is my best flower picture :)

 

"White" or near "white" in a UV picture might mean the area is highly UV reflective. Or is pushed in processing to appear bright.

 

I must confess I process my images in Lightroom by adjusting the dark, white, shadows and highlights, within reasonable limits, in order to make the image more appealing to the eye.

Do you suggest not to do any processing beside sharpening, noise reduction and white balance?

 

For this UV picture in particular I just made the background darker in order to make the "white" flowers stand out more.

(to be sure I just compared the processed UV image with the raw UV image, the flowers have the same "brightness" in both picture).

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You may edit (process) your images as you see fit. All the tasks you mention are well-respected in digital conversions - including UV/IR work. The only request we make is that you attempt to reproduce the white-balanced false colour tones of blues, yellows and grays/blacks/whites so that we can show that a given UV flower signature is uniform across different platforms (but similar filters). This is typically done using whatever white balance target and conversion tools you have available. It seems like this is exactly what you have done!

 

Congratulations on your first formal botanical post!!! We look forward to many more.

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Hornblende

Thanks Andrea :)

 

I would post a lot of flower species if I could.

The wind is my worst enemy! It is really difficult to have a good, sharp picture of flowers in UV, even with only a very faint breeze. I think you know that very well ^^.

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If you plan on shooting flowers on regular basis in UV, getting a UV-capable flash is a big benefit. It also save your hair from greying prematurely.

 

I do 97% ++ of my UV flowers with flash, by the way. Usually SB-140, in studio with Broncolor studio flashes with uncoated Xenon tube.

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Hornblende

I am gonna try to get the Vivitar flash, there is plenty of them for less than a hundred bucks on Ebay.

I have one question tho, could I use this flash without any kind of UV-pass filter in front of it?

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If the flash unit emits a healthy amount of UV, the better option is having the bandpass filtration at the lens (or camera) level. There will be loads of IR as well (all electronic flash tubes emit IR) , but the filter should take care of that provided the UV:IR ratio isn't too low. However, if the flash delivers too little UV, the resulting s/n of the flash system will be insufficient and you end up with IR contamination of your allegedly UV-only image.

 

Most flash units require some modification as they usually are designed to cut UV by help of the coatings on the flash tube and/or flash window.

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