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Luffa aegyptiaca [Luffa]


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#1 msubees

    Zach Huang

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Posted 23 May 2015 - 21:09

Huang, Z.Y. (2015) Luffa aegyptiaca Mill. (Cucurbitaceae) Luffa. Flowers photographed in ultraviolet, visible light and simulated insect vision. http://www.ultravioletphotography.com/content/index.php/topic/1382-luffa-aegyptiaca-luffa/

Beijing, China
22 Sept, 2014
Cultivar in vegetable garden.

Comments: This plant is widely planted in China and the rest of Asia. Young fruits are usually made into a soup that has a sweet taste and old ones produce a natural sponge-like material that is used for dish-washing or for bath-scrubbing. Luffa is also available now at Meijer in Michigan, perhaps due to an expanding Asian population. There are two species of luffa, one that is smooth (Luffa aegyptiaca) and one that has ridged surface (Luffa acutangula).
I have previously seen many bees visiting this flower, perhaps for both nectar and pollen. They are not highly attractive to bees, so visits by honey bees happen usually only in the fall (Sept to Oct).

Synonyms:
  • Cucurbita luffa hort.
  • Luffa cylindrica M.Roem.
  • Luffa aegyptica (lapsus)
  • Luffa pentandra Roxb.
  • Momordica cylindrica L.
  • Momordica luffa L.
Common Names:
  • Luffa, loofah, 丝瓜 sigua (Chinese)
Comment:
Photographs taken with both female and male flowers, in the order of visible light, ultraviolet, and simulated insect vision.

Reference:
1. Wikipedia (23 May 2015) Luffa aegyptiaca. Wikimedia Foundation, San Francisco, CA.


Equipment [Panasonic DMC-G5-broadband + El Nikkor 80mm f/4.5 old format]

Set A, a male flower.

1. Visible Light [f/8 for 1/30" @ISO160, S8612 (1.75 mm thick), natural light]
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2. Ultraviolet Light [f/8 for 15" @ISO160, S8612 (1.75 mm thick) and UG 11 (1 mm thick), natural light]

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2b. 100% crop of the flower showing trichomes (hairs) that absorb UV and shown as dark.
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3. Simulated Insect Vision [f/8 for 4" @ISO160, S8612 (1.75 mm thick) and UG 5 (1.5 mm thick), natural light]
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Set B, a female flower. UV signatures are very similar.

4. Visible Light [f/8 for 1/200" @ISO160, S8612 (1.75 mm thick), natural light]
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5. 2. Ultraviolet Light [f/8 for 1.3" @ISO160, S8612 (1.75 mm thick) and UG 11 (1 mm thick), natural light]
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6. Simulated Insect Vision [f/8 for 1/4" @ISO160, S8612 (1.75 mm thick) and UG 5 (1.5 mm thick), natural light]
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Edited by Andrea B., 26 June 2015 - 23:30.


#2 colinbm

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Posted 24 May 2015 - 02:10

These are excellent Zach
Do you CWB off PTFE, with each setup ?
Col

#3 msubees

    Zach Huang

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Posted 24 May 2015 - 03:11

Col,

thanks. yes, I do for both UV and bug vision. for visual I use auto WB. G5 is nice since it has 2 custom WBs, but my Nex7 now has only 1. so I now have to shoot the PTFE square often. should build a profile in photoninjia to avoid this.

View Postcolinbm, on 24 May 2015 - 02:10, said:

These are excellent Zach
Do you CWB off PTFE, with each setup ?
Col


#4 colinbm

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Posted 24 May 2015 - 04:00

Thanks Zach
I don't get this result with my CWB on a PTFE block ?
eBay seller, UVIROptics, has some sintered fibrous PTFE now, so I am looking forwards to trying this out.
Col

#5 msubees

    Zach Huang

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Posted 24 May 2015 - 14:26

Collin,

I used "virgin PTFE" as suggested by Igor, then Steve (UVIROptics) suggested me sanding the surface, which I did. I also ususally use 2-3 bars (perhaps -1 EV?) underexposure with G5. Now my Nex7 always gave me error, but it still seems to be ok with WB. but only one!

#6 Andrea B.

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Posted 24 May 2015 - 17:56

Excellent work, Zach. Thanks for posting this. I think this is our very first UV photo made in Beijing - cool!!

For some subjects, it's never a perfect call between the wildflower or cultivar designation. Given that the Luffa is so widely cultivated and that you saw it in a garden setting, the cultivar placement was probably the correct one. I should mention that I have a plan to add links in the wildflower section to all the cultivars.

For completeness, I added the 'simulated insect vision' to your reference string at the top of the post. :( That way if your post is ever referenced elsewhere (we hope someday!!) it will be more descriptive.

Interesting those UV-dark trichomes.
Andrea G. Blum
Often found hanging out with flowers & bees.

#7 msubees

    Zach Huang

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Posted 24 May 2015 - 20:59

Thanks, Andrea. I have a pumpkin flower from Taiwan :( :) not sure if it is done here or not.

And I have "wild cucumber" also done in UV, but not in bug vision.

Edited by msubees, 24 May 2015 - 21:00.