NikonGear'23
Gear Talk => Lens Talk => Topic started by: Dr Klaus Schmitt on April 05, 2020, 16:23:08
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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:
(https://1.bp.blogspot.com/-glY-ENxp52U/XonYyYHJWmI/AAAAAAAABFs/mGBxmV1gxeEVnplTahXGVBBIrLEDBUEowCLcBGAsYHQ/s1600/Phlox%2BUV%2B2%2B%2528M%2529%2Bopt.gif)
Phlox flower in A-mode i.e. exposure compensated:
(https://1.bp.blogspot.com/-MEuNiBUcOnY/XonY0iqe9xI/AAAAAAAABFw/qApSyesNcA8KWAVIqK168_ta36sxcIVhQCLcBGAsYHQ/s1600/Phlox%2BUV%2B1%2Bopt.gif)
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Interesting. So, basically, the surrounding foliage and stems change more than the flower itself?
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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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Btw. man-made structures do show quite some polarizing effects...
(https://1.bp.blogspot.com/-pcdcN8VAhrI/XnJCYxM-qLI/AAAAAAAABDY/RNaZVik_zZIyJJJ7Xss9s9N2Yl_OjSYawCLcBGAsYHQ/s1600/Uv%2BPolarizer%2BRoof2.gif)
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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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?
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Interesting finding ;)
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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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Thank you!
It is a nice blue color.
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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.
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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:
(https://1.bp.blogspot.com/-x_067eogT9g/Xox-qByNC8I/AAAAAAAABGQ/TT0f_Puvhik3PWcxmX-llTBO78NOcsQGACEwYBhgLKs4DAMBZVoBf2yUHEj18VblP2DGrCE51zJcMsMLmzp5yOgnHrJuYSzbYg8wPnv6S_k_UO5OyDZsdYnYrK8dseJJidtl_SVE2lSaZXtx3jkNLIipb3793Rl5c0kFTXoGv0NIdcnpB73PxQd2Ea2u2g1G2Q0qp8jK96KC-ZaEHw28zZ7rEM2cHvjE85c7qnnKrjJ10It6wMTDiEGAM8D1Ry5v1y-zzOUXoK-AwijakxxmeQxX4q03Bs6uIPDpyRCKWjN7FjPHeXCecieMA-14hzguZGABy9aLFM28KSqxVhtwRPyUltHQ4J7kLggjdoeJxbmx7LVQqhfjhz6W5zleEir6I8YYgAVt-4fm5KG9VAzl8IRUVK6axVbCqg7iSJHoUocu4lT9ocvtn-lf6oqBWedkmILX95Ut5t2lGQAr0ry8c9GAZeoTuw6iLHbM_-vnLChcXi0L0NDHooui846B0S1ILuYSvZiEVxK1nHVn8truUQGFdhgxr-OPiOf6EP2WWtMwCfJZvG0a1_EtyK8hjtaM_Pi8yOnAaZqO3iv0n-C9kA4jZHR9cRFOIDMuvuvSWrWEWR6Tqf3zNUCqvrtxFyvInONUPah9kK9FpP0Biu6MYMOCCsvQF/s1600/Saxifraga%2Bwhite%2Bcirc%2Bpol%2BUV%2B20200407%2B%25282%2529.gif)
Reflected polarized UV, only sunlight:
(https://1.bp.blogspot.com/-A6WC_2VSAaY/Xox-nA73xNI/AAAAAAAABGM/A5IqNBpwWwoN2yfl52Mc3e1uGxD4JU8BQCEwYBhgLKs4DAMBZVoB5fS0vVs1qr21pUPkDLcVhlJ8nn_VlyeoZUL2qLGxvHkiNznrQfg00TnsIRzRlUIAMtX1bJeFPy3t933woVM83xSBjgbewS3NiZploAyF7zC-V7lUF83z2vLGp28FbQCCHMr7m-_DJGLHE9KcptxSvXN6CzR4dteZEEFIo165fmxyLqSO-4NQ-wHOqMI3MgaJMvJApKqzD_6lDWYOfOX5fZPNpQY42xm6yAvPPh-2jSglOLjBMKPIRjA5GXxT31b-FswZtuUiS0QAGdK7cbAz9Rp14b5pomActtgw7ldc2xgmxArIwTDuRh4RHdXgN17MLqxTuufmh4RlhXyog905vNpXQTNi3Hr3BGkEjjChwhzo087IgIlBVtMjgTbm0PXtqGQRSJYwjluqfVOASJQzz7pYbgHVKNBxTKD-yhYeXttoHkd93g2PdvdN_RtcyP1r6TM45o3zN1CyTM2oH06Ip-B18hGegVgEOc39QbLQW4eAq9FIAnKvkwUUmkSRZMmajSV7tmwClmc-6RLLvuw0TT0jL9eBjqBYbMr5QVp_H7mRo0WlG3_TOj1mKG6Gd1v1IhYyBEbOcMAZnDSD5F45Ar3OwFUzRjndPML2CsvQF/s1600/Saxifraga%2Bwhite%2Bcirc%2Bpol%2BUV%2B20200407%2B%25281%2529.gif)
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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?
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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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Very nice!
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Very nice!
Thanks Toby!
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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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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).
(https://a4.pbase.com/o12/08/747708/1/170609642.2SToqRXD.XPOLtests04590dVISUV20200411_c.jpg)
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Very nice Klaus.
Did you test the old Zeiss Bernotars as well?
Yes I did, they somewhat work, but not very deep into UV and with rather low transmission...
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The Zeiss Bernotar were introduced in the 1930ies. I have found a paper from 1939/1940 by J. Wempe testing it for astronomy purposes. He has a transmission chart in that paper showing a strong drop down past 400nm. At 365 it was already very close to zero. In that paper it is also mentiones, that Zeiss made some special Bernotar filters „with very clear glass“, that were good a bit deeper into UV.
The picture with the aluminum is interesting, as the reflection on the „metal“ is going down as well. Maybe that is because there is always an oxide layer on Al, though only a couple of nm thick (you can grow it into the micro meter range). This layer is used in metallography on Al to reveal the crystal orientation of grains. The samples are polished, anodized (Barker) and then investigated with polarized light. Different orientation then gives different colors.
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The Zeiss Bernotar were introduced in the 1930ies. I have found a paper from 1939/1940 by J. Wempe testing it for astronomy purposes. He has a transmission chart in that paper showing a strong drop down past 400nm. At 365 it was already very close to zero. In that paper it is also mentiones, that Zeiss made some special Bernotar filters „with very clear glass“, that were good a bit deeper into UV.
The picture with the aluminum is interesting, as the reflection on the „metal“ is going down as well. Maybe that is because there is always an oxide layer on Al, though only a couple of nm thick (you can grow it into the micro meter range). This layer is used in metallography on Al to reveal the crystal orientation of grains. The samples are polished, anodized (Barker) and then investigated with polarized light. Different orientation then gives different colors.
Here, I measured the transmission(s) as I found two types of Bernotar (maybe older/younger); indeed it does drop in transmission significantly beyond 400nm. But Zeiss Jena made dedicated UV polarizers, too which work to 300nm and beyond. Interesting about the aluminum.
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That graphs are taken with non pol. light. The polarisation effect drops in to the red, so the transmission increases there. The graphs in the above mention paper are very similar to yours, but not as detailed.
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That graphs are taken with non pol. light. The polarisation effect drops in to the red, so the transmission increases there. The graphs in the above mention paper are very similar to yours, but not as detailed.
Yes Werner, I have the published Zeiss Jena graphs too and they are quite similar to mine,
also what they published about their UV polarizers which I'm happy to have found.
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So today about Lewisia - Cliffmaids in reflected and polarized light
(https://1.bp.blogspot.com/-xNubZ5Qk7ng/Xpb49Grth9I/AAAAAAAABGk/0Ax5o4TFR4YwxqxvB6gYmSZERyOtXiKQgCLcBGAsYHQ/s1600/Lewisia%2BUV%2BPOL%2B200415%2Brev%2Bopt.gif)
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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 (https://en.wikipedia.org/wiki/Polarized_light_microscopy#The_Michel-Levy_chart)
(https://a4.pbase.com/o12/08/747708/1/170635357.x3bjL8iz.MICAPolVISUVBVBU20200419opt.gif)
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Different approach used here, delivers more intense colors...
(https://a4.pbase.com/o12/08/747708/1/170640118.cXQY6uW0.MICAXPOL20200421opt.gif)
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Gazania rigens in polarized reflected UV light
(https://a4.pbase.com/o12/08/747708/1/170659758.g7cZaVz8.GazaniaUV2020r1.gif)
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And there is an interested effect possible, I call it the "MIDAS effect" ...
(https://a4.pbase.com/o12/08/747708/1/170650988.fH2Ol5Z8.P1780775g1_c.jpg)
and SILVER also works...
(https://a4.pbase.com/o12/08/747708/1/170650991.RIf09Fio.P1780899g2_c.jpg)
and no plant was harmed doing this, an no spraycan was used ;-)