• Ultraviolet Photography
  •  

Cucurbita pepo (Variegated Acorn Squash)

Multispectral
4 replies to this topic

#1 Mark

    Member

  • Members(+)
  • 309 posts
  • Location: Massachusetts, USA

Posted 31 October 2017 - 22:14

Hello all,

Picking up where I left off last winter (during which time I shot a lot of foods, on account of the lack of wild living subjects), allow me to present this acorn squash, along with an example of one of the benefits of shooting otherwise inanimate subjects - which, pointedly, don't wilt (move) over the course of shooting a multispectral set.

This variety does look more decorative than edible to me, but I'm sure its just as delicious once baked with all the fixings.
Attached Image: 10-08-2017_19-32-59_baaderstack.jpg

Looking at it under UV I see the lighter patches are quite UV reflective and push a lot through the filter's VIS bleed just over 400nm, while the darker/green areas are UV dark.
Attached Image: 10-08-2017_19-28-40_andreau.jpg

The UVIVF shot is markedly glowing with red fluorescence where all the green/UV dark areas were (understandably, I'd say). I'm very happy with the results here.
Attached Image: 10-08-2017_19-29-58_baaderstack.jpg

While the IR image has the cream & light blue tones I like, it just doesn't have the same aesthetic appeal as a whole flowering plant IMO.
Attached Image: 10-08-2017_19-35-12_r72.jpg

Moving up to the camera's IR limits the subject looks lifeless, flat, boring, just a zombie version of itself.
Attached Image: 10-08-2017_19-39-39.jpg

On the other hand, looking at its UVIIF image it not only is vibrant, but wow - so much glowing! One thing I notice here in particular is the complete lack of any gray/blue areas, which I commonly see in certain parts of plants/flowers (typically petals, etc). This gives me a clue / some insight into what I'm seeing in those other images. Here though, I'm happy with this result, looking like an ember freshly pulled from the fire.
Attached Image: 10-08-2017_19-36-02_r72-uviif.jpg

About that benefit of shooting still subjects... I did not move the subject, adjust focus, or touch the camera in any way between the VIS and UVIVF captures (triggered via remote control). This resulted in VIS and UVIVF images which were practically perfectly aligned. Taking the VIS image and subtracting it from the UVIVF image left what is about as close as I've ever been to a strictly fluorescence-only image (albeit derived in part computationally). I know its not a perfect process, because running it in reverse produces an imperfect VIS result. But still, rather striking I'd say!
Attached Image: uvivfvissubraction.jpg

Shooting info:
Camera
- Nikon D750 [broadband] + 50 mm Nikon Series E lens + 12 mm extension tube
Lens filters
- UV: AndreaU-MKII
- VIS & UVIVF: KV418 + 420 nm LP + Baader UV-IR cut [stack]
- IR & UVIIF: Hoya Y(K2) + R72

- Extended IR: Xnite830 + 1K nm longpass [stack]
Illumination/Irradiation
- VIS: White LED bulb
- UV & UVIVF: 4 x 18" T8BL-B + FL-02 glass
- UVIIF: 2 x [MTE-U303 + Hoya U340]
- IR: 40 W incandescent clear glass bulb
Exposures

- 0.05-20 s
- ISO320
- f11


#2 Andrea B.

    Desert Dancer

  • Owner-Administrator
  • 5,172 posts
  • Location: USA

Posted 02 November 2017 - 15:50

I don't (currently) have a photo app which will subtract. What is the underlying formula/computation for that? (Approximately.) Is it literal R, G and B subtraction?

That is indeed a striking result. And I like the way you have presented it with the smaller insets. Very nice.
Andrea G. Blum
Often found hanging out with flowers & bees.

#3 Andrea B.

    Desert Dancer

  • Owner-Administrator
  • 5,172 posts
  • Location: USA

Posted 13 November 2017 - 20:33

Hi Mark -- I made a minor alteration to the title to satisfy the format in the Botanical sections (necessary for index creation). The forum software has a tool to make the linking easier that I asked you about. Look for your linked Acorn Squash here: UV Cultivars: Vegetables, Herbs & Crops When you click on the title there, it will bring you here to your original post. Cool, eh? :D

I don't really need to add the word "Link" to the linked title. Maybe I'll drop that. I used it originally when linking some garden cultivars in the wildflowers section to kind of emphasize that the linked thing was not a wildflower.
Andrea G. Blum
Often found hanging out with flowers & bees.

#4 Mark

    Member

  • Members(+)
  • 309 posts
  • Location: Massachusetts, USA

Posted 16 November 2017 - 00:22

Thanks Andrea. Next time I have a post(s) of worthy content I'll try putting it in proper/official format right from the start.

P.S. - An interesting side note regarding the link you created... on the "My Content" page the link you created only shows up as Unread (bold text, highlighted line, ...). It does not change status even though I've clicked through it several times and refreshed the page. I think the routing for that kind of link is not recognized by the forum software. I'm not complaining or anything to that affect, just FYI, that's all.

Edited by Mark, 16 November 2017 - 00:28.


#5 Andrea B.

    Desert Dancer

  • Owner-Administrator
  • 5,172 posts
  • Location: USA

Posted 16 November 2017 - 06:23

You wouldn't need to add too much more to make a formal post when you have the time. Just the initial credit string, alternate names (if any) and a reference of some kind at the top. The rest of your typical posts would be acceptable as is.

I'll check out the problem you mention. I just want to make sure I didn't do something wrong. Thanks for letting me know.
Andrea G. Blum
Often found hanging out with flowers & bees.