Author Topic: UV Nikkor 105mm and polarizer  (Read 967 times)

Dr Klaus Schmitt

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UV Nikkor 105mm and polarizer
« on: April 05, 2020, 16:23:08 »
Here today a bit about using the UV-Nikkor 105mm in polarized light, using a PHLOX - Rockfoil flower
and a deep reaching (up to 320nm) circular polarizer in front of a Baader UV filter (320-390nm), so this
is reflecetd UV btw.

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



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

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Birna Rørslett

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Re: UV Nikkor 105mm and polarizer
« Reply #1 on: April 05, 2020, 18:07:00 »
Interesting. So, basically, the surrounding foliage and stems change more than the flower itself?

Dr Klaus Schmitt

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Re: UV Nikkor 105mm and polarizer
« Reply #2 on: April 05, 2020, 20:54:43 »
Interesting. So, basically, the surrounding foliage and stems change more than the flower itself?

In this case yes. Just talked to a friend and Professor for insect sensory perception and bees on the
outer rim of their eyes have sensors for polarization he said. So I am looking forward to highly
reflective flowers like the inside of tulips etc. There should be some interesting things to see! Just
all parks here are closed, so no access...
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Dr Klaus Schmitt

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Re: UV Nikkor 105mm and polarizer
« Reply #3 on: April 05, 2020, 20:58:54 »
Btw. man-made structures do show quite some polarizing effects...



This was shot using a special Zeiss Jena UV-Polarizer which works down to 300nm (but is this case there is only down to 340-350nm visible)
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MEPER

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Re: UV Nikkor 105mm and polarizer
« Reply #4 on: April 05, 2020, 21:06:53 »
Regarding the blue flower I like the first image most where the flower reach the darkest blue color.
Possible to post that as a still image?

Erik Lund

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Re: UV Nikkor 105mm and polarizer
« Reply #5 on: April 06, 2020, 13:06:22 »
Interesting finding ;)
Erik Lund

Dr Klaus Schmitt

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Re: UV Nikkor 105mm and polarizer
« Reply #6 on: April 06, 2020, 14:01:47 »
Regarding the blue flower I like the first image most where the flower reach the darkest blue color.
Possible to post that as a still image?

Here...
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Re: UV Nikkor 105mm and polarizer
« Reply #7 on: April 06, 2020, 14:20:24 »
Thank you!
It is a nice blue color.

dickb

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Re: UV Nikkor 105mm and polarizer
« Reply #8 on: April 07, 2020, 12:32:10 »
Was the light on the background constant when you took the Phlox series? The variation in brightness in the background reminds me of what you would see when sunlight filters through leaves on a windy day.

Dr Klaus Schmitt

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Re: UV Nikkor 105mm and polarizer
« Reply #9 on: April 07, 2020, 15:31:28 »
Interesting. So, basically, the surrounding foliage and stems change more than the flower itself?

Here another example (white Saxifraga flowers), which shows the predicted effect my friend told me about:

Reflected polarized UV, using a 365nm UV LED:




Reflected polarized UV, only sunlight:

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Jack Dahlgren

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Re: UV Nikkor 105mm and polarizer
« Reply #10 on: April 07, 2020, 18:34:34 »
I'm not quite sure what behavior is being displayed and whether it is different with UV rather than the rest of the spectrum.
One would expect that the same sort of polarized reflection which obeys Brewster's angle.

https://en.wikipedia.org/wiki/Brewster%27s_angle

While index of refraction is different for UV, the principle is the same.

What should I be looking for in these images?

Dr Klaus Schmitt

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Re: UV Nikkor 105mm and polarizer
« Reply #11 on: April 09, 2020, 01:03:54 »
Was the light on the background constant when you took the Phlox series? The variation in brightness in the background reminds me of what you would see when sunlight filters through leaves on a windy day.

Yes it was Dick, it only took short to take those 8 shots...
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Toby

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Re: UV Nikkor 105mm and polarizer
« Reply #12 on: April 09, 2020, 02:26:08 »
Very nice!

Dr Klaus Schmitt

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Re: UV Nikkor 105mm and polarizer
« Reply #13 on: April 10, 2020, 23:26:49 »
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Alaun

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Re: UV Nikkor 105mm and polarizer
« Reply #14 on: April 11, 2020, 11:54:09 »
Very nice Klaus.

Did you test the old Zeiss Bernotars as well?

(D810 full spectrum, UV Nikkor 105mm, Baader U, Zeiss Bernotar)

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