Polarized Reflected UV Photography

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kds315*
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Polarized Reflected UV Photography

Post by kds315* »

Today (after some too long hiatus) a bit about Polarized Reflected UV Photography, using a PHLOX - Rockfoil flower and a deep reaching (up to 320nm) circular polarizer in front of a Baader UV filter (320-390nm). Multiple images assembled into a animated gif.

Phlox flower in M-mode i.e. non exposure compensated:

Image

Phlox flower in A-mode i.e. exposure compensated:

Image

These are some early experiments, of course there is room for improvement, like stacking each pol filter position to get more DOF etc. but first things first...
Klaus

http://www.macrolenses.de for macro and special lens info
http://www.pbase.com/kds315/uv_photos for UV Images and lens/filter info
http://photographyoftheinvisibleworld.blogspot.com/ my UV diary

kds315*
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Post by kds315* »

Here another example (white Saxifraga flowers), which shows the predicted effect my friend told me about: That bees have around their eyes sensors able to detect polarized light and there woud be flowers using that:

Visible Light - Sunlight:

Image


Reflected polarized UV, only sunlight:

Image


Reflected polarized UV, using a 365nm UV LED:

Image
Klaus

http://www.macrolenses.de for macro and special lens info
http://www.pbase.com/kds315/uv_photos for UV Images and lens/filter info
http://photographyoftheinvisibleworld.blogspot.com/ my UV diary

Macro_Cosmos
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Post by Macro_Cosmos »

Interesting results! Reflected polarised light and in UV, looks very trippy.

I've been doing some PPL/XPL stuff recently. I'm thinking about automating the polariser's rotation so I can do video. A rubber wheel that's pushed against the polariser, should work out very well.

kds315*
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Post by kds315* »

Macro_Cosmos wrote:Interesting results! Reflected polarised light and in UV, looks very trippy.

I've been doing some PPL/XPL stuff recently. I'm thinking about automating the polariser's rotation so I can do video. A rubber wheel that's pushed against the polariser, should work out very well.
Ineresting idea to automate that!!
Klaus

http://www.macrolenses.de for macro and special lens info
http://www.pbase.com/kds315/uv_photos for UV Images and lens/filter info
http://photographyoftheinvisibleworld.blogspot.com/ my UV diary

kds315*
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Post by kds315* »

Polarization is an effective tool in photography and cross-polarization is well know to allow to suppress shine and reflections from certain surfaces.

Here a few tests I have made after having been able to find suitable UV polarizers using a glass vase standing on an aluminum lab jack.

Visible light on top, reflected UV light at bottom. Zero, 45 and 90 degree polarizer angles (left to right).

Image
Klaus

http://www.macrolenses.de for macro and special lens info
http://www.pbase.com/kds315/uv_photos for UV Images and lens/filter info
http://photographyoftheinvisibleworld.blogspot.com/ my UV diary

kds315*
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Joined: Mon Feb 02, 2009 1:06 am
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Post by kds315* »

So today about Lewisia - Cliffmaids in reflected and polarized light

Image
Klaus

http://www.macrolenses.de for macro and special lens info
http://www.pbase.com/kds315/uv_photos for UV Images and lens/filter info
http://photographyoftheinvisibleworld.blogspot.com/ my UV diary

MarkSturtevant
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Post by MarkSturtevant »

That is very interesting. I know that some flowers will use UV reflective colors to communicate with bees. Some have stripes or other patterns as 'guides' to lead bees to the center -- communication between flowers and bees that we don't normally get to see.
Mark Sturtevant
Dept. of Still Waters

kds315*
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Post by kds315* »

MarkSturtevant wrote:That is very interesting. I know that some flowers will use UV reflective colors to communicate with bees. Some have stripes or other patterns as 'guides' to lead bees to the center -- communication between flowers and bees that we don't normally get to see.
Thanks, yep indeed they do use this.
Klaus

http://www.macrolenses.de for macro and special lens info
http://www.pbase.com/kds315/uv_photos for UV Images and lens/filter info
http://photographyoftheinvisibleworld.blogspot.com/ my UV diary

kds315*
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Post by kds315* »

Well this is a bit on the scientific side, sheet Mica in polarized UV and visible light, different pol. angles.
If interested about the colors and why, I refer to the work of Mr Michel-Levy https://en.wikipedia.org/wiki/Polarized_light_microscopy#The_Michel-Levy_chart

Image
Klaus

http://www.macrolenses.de for macro and special lens info
http://www.pbase.com/kds315/uv_photos for UV Images and lens/filter info
http://photographyoftheinvisibleworld.blogspot.com/ my UV diary

kds315*
Posts: 223
Joined: Mon Feb 02, 2009 1:06 am
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Post by kds315* »

Different approach used here, delivers more intense colors...

Image
Klaus

http://www.macrolenses.de for macro and special lens info
http://www.pbase.com/kds315/uv_photos for UV Images and lens/filter info
http://photographyoftheinvisibleworld.blogspot.com/ my UV diary

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