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UltravioletPhotography

[UVIVFL] Banana spots


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Bananas are healthy and all know they taste the best when fully ripen. Unfortunately they also then develop massive brown spots which lead many to avoid the fruit at that stage.

 

The following sequence was taken when I tested a recently acquired 40 mm f/2.8 Micro-Nikkor to see whether it would cover the entire FX frame for close-ups (it did).

 

Visible light, Nikon Df , AFS Micro-Nikkor 40 mm f/2.8 G, Broncolor flash, Baader UV/IR Cut filter. Camera set to record in FX format.

UVP_Banana_VIS_T1411217476.jpg

 

Same camera/lens, but a Kodak 2E replacing the Baader filter. Nichia UV 365 torch.

UVP_Banana_UVIFL_T1411217459.jpg

 

It is quite interesting to observe the extended area of detail shown by UV-induced visible fluorescence. The spots are surrounded by a bright fringe fanning out in a radial manner and encircled by smaller bright points. Nothing of this can be seen in visible light.

 

As far as I know, the browning is a chemical response caused by ethylene and other growth hormones being released into the banana peel as the fruit ripens. Despite this one easily gets a perception of spreading rot fungi and hyphae in the fluorescence record. I found no literature references to the actual presence of fungi though.

 

On a tangential note, the ever-present Colorchecker Passport has a lot of fluorescence in it.

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Yes, I certainly have. Besides, darkness has conquered my world now as we're entering the long winter and that entails long and boring evenings. Perhaps I can take a break from other commitments and indulge in photomacrography with bananas.
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Great! I also plan to look closer and closer at nature.

Cold weather around here has finally made it uncomfortable to be crouched in the woods capturing the denizens of the forest floor so I too plan to go into inside mode for the most part. Winter is different for you I suspect. The coldest it gets in NJ is in the single digits very occasionally and sometimes a foot or two of snow at different intervals. In which case there is a rush to the stores to gobble up all the bread and milk. I sit back and watch the buffoons scramble like they are gong to starve without a full cupboard. We are light years from hunter gatherers these days--which is probably good as there would be nothing left to gather with the population we have now.

 

Anyway, your pollen shots in the visitors gallery--was that with extension tubes or bellows?

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If you refer to the Mirabilis jalapa, that was conducted using a Macro-Nikkor 65 mm f/4.5 lens on a Nikon Multiphot. So lots of bellows draw there.
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