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Shiny Metal Test in UVIVF Photogaphy

Fluorescence
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#1 Damon

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Posted 21 February 2015 - 03:09

Admin Note: See description of Ball Bearing Test, aka Shiny Metal Test in the next post (#2).
Please post some good examples of your ball bearing or shiny metal tests to this thread. Thanks!!
***************************

I am starting a new thread so we can keep the Blak-Ray reference page clean.

Shane, I like your description about the chrome ball test. I am wondering though if it at all depends on exposure factors. At some point (.25s), even with my recent amateur chrome hub cap test, there was no light from the Blak-Rays visible. It was only when the shutter speed became longer did it start to appear. How do we account for that variable? Or am I confusing something.

I apologize for not completing my proper bearing test. Tomorrow.

-D

#2 Andrea B.

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Posted 21 February 2015 - 13:09

Shiny Metal Test in UVIVF Photography
from Shane Elen

Capturing fluorescence (spectrally or photographically) works on the principle that the combined effect of the excitation and emission filters allows only fluorescence emission to reach the camera sensor. Excitation wavelengths from the excitation illumination must be totally excluded.

For UV-induced Visible Fluorescence photography, the UV illumination must be filtered for UV-only output, and the lens must filtered for Visible-only input. To test that the filtration is working properly, photograph some shiny ball bearings (which are non-fluorescent, of course) in total darkness. If the filtration is working properly, then the ball bearing is not visible. If the ball bearing is visible (shows a shiny reflection), then there is leakage in the filtration which must be remedied in order to claim proper UVIVF photography.

When using a broadband camera or a camera with a weak internal filter, it might be difficult to determine whether filtration leakage is from stray Visible or Infrared output from the UV illumination source or whether it is from some UV getting through a mediocre UV/IR-blocker filter on the lens. Further tests using additional filtration might be useful to sort this out.

Stray light leakage might could potentially wash out Visible fluorescence depending on how much and what type of leakage there is. It could also illuminate non-fluorescent areas of the subject.
Andrea G. Blum
Often found hanging out with flowers & bees.

#3 Andrea B.

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Posted 21 February 2015 - 13:12

UV Source: Nichia 365 UV-Led Torch
Metal: Stainless Steel Spoon

Comment: The exposure times should be equal, but this is all I have for now. I will replace it later with an improved version. At least it illustrates the problem.

D600-broadband + Zeiss 60/4.0 UV-Planar + Baader UV/IR-Cut Filter (on lens) + Unfiltered Nichia 365 UV-LED
f/4 for 1.6" @ ISO-400 in total darkness
Unfiltered UV Source showing visible violet leakage. Only the lens is filtered.
Attached Image: poinsettia365UVLedUNFiltered_4BaaderCut_20141224wf_28532pf1pn2.jpg

D600-broadband + [Zeiss 60/4.0 UV-Planar + Baader UV/IR-Cut Filter (on lens)] + [Nichia 365 UV-LED + Baader-U UV-Pass FIlter (on light)]
f/4 for 1.3" @ ISO-400 in total darkness
The violet leakage is considerably reduced when a UV-pass filter is used on the source illumination.
Attached Image: poinsettia365UVLedFiltered_4BaaderCut_20141224wf_28536pf.jpg
Andrea G. Blum
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#4 Andrea B.

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Posted 21 February 2015 - 13:21

Damon, I agree that 'leakage' is perhaps not absolutely defined in this situation? As has been so often noted, we can force UV or IR light through any lens with a long enough exposure. So if there is some minor contamination from a certain illumination source against which it is difficult or impossible to completely filter, then perhaps the length of exposure time can control it a little?
As noted, I'm not sure about this either. When Shane gets a minute, perhaps he will give us some insights. :D
Andrea G. Blum
Often found hanging out with flowers & bees.

#5 Damon

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Posted 23 February 2015 - 01:56

I updated my test. I think Shane is correct in his original statement saying that if you have no leakage the item will be invisible/black

The results of this test tell me that No IR is getting my sensor with the Baader UV/IR cut filter on the camera.

It must be pitch "can't see your hand in front of your face" black to do this. In my shack, a beer bottle and other odds and ends were still illuminating the darn picture when the shutter went long.
Despite that, the IR image never surfaced.

Andrea, your image shows a little something on the second shot--that's visible from the LED I bet.

See Below:
All images are untouched RAW files converted to JPEG to try to ensure consistency
If you see little blue specks those are cotton fibers.


IR Test: Canon 1D Mark IV Unmodified, EL-Nikkor 80mm f5.6, 2 Blak-Rays, Darkness, 1 s @ f/8 ISO 200, No filters on lens, Sunny WB
Attached Image: IR test_Blak-Ray No Filters on Camera_resize.jpg


IR Test: Canon 1D Mark IV Unmodified, EL-Nikkor 80mm f5.6, 2 Blak-Rays, Darkness, 1 s @ f/8 ISO 200, New Baader UV-IR-Cut Filter on camera lens, Sunny WB
Attached Image: IR test_Blak-Ray New Baader UV-IR Cut Filter on Camera 1s iso200_resize.jpg


Here is where Shane's directions should be followed to the letter. No glowing stuff nearby. I had no "visible" light in my shack but a fair amount of stuff that was casting their own Visible Fluorescence, even from a distance--with which they started to light up enough to see the spoon itself at long shutter speeds. Nowhere does the IR image appear though.
IR Test: Canon 1D Mark IV Unmodified, EL-Nikkor 80mm f5.6, 2 Blak-Rays, Darkness, 5 s @ f/8 ISO 200, New Baader UV-IR-Cut Filter on camera lens, Sunny WB
Attached Image: IR test_Blak-Ray New Baader UV-IR Cut Filter on Camera 5s iso200_resize.jpg


IR Test: Canon 1D Mark IV Unmodified, EL-Nikkor 80mm f5.6, 2 Blak-Rays, Darkness, 15 s @ f/8 ISO 200, New Baader UV-IR-Cut Filter on camera lens, Sunny WB
Attached Image: IR test_Blak-Ray New Baader UV-IR Cut Filter on Camera 15s iso200_resize.jpg


That weird thing in the middle with the lighter perimeter is actually the reflection of the Blak-Ray housing, somewhat distorted by the curvature of the spoon surface. No magenta at 30's.
IR Test: Canon 1D Mark IV Unmodified, EL-Nikkor 80mm f5.6, 2 Blak-Rays, Darkness, 30 s @ f/8 ISO 200, New Baader UV-IR-Cut Filter on camera lens, Sunny WB
Attached Image: IR test_Blak-Ray New Baader UV-IR Cut Filter on Camera 30s iso200_resize.jpg


Thought I might as well try out the MTE UV LED light while I was at it.
IR Test: Canon 1D Mark IV Unmodified, EL-Nikkor 80mm f5.6, Unfiltered MTE Nichia 365 UV-LED, 1/10 s @ f/8 ISO 200, No filter on lens, Sunny WB
Attached Image: IR test_MTE 301 No Filter on Camera 1-10s iso200_resize.jpg


IR Test: Canon 1D Mark IV Unmodified, EL-Nikkor 80mm f5.6, MTE Nichia 365 UV-LED filtered with a Baader U, 1/10 s @ f/8 ISO 200, New Baader UV-IR-Cut Filter on camera lens, Sunny WB
Attached Image: IR test_MTE 301New Baader Uv-IR cut Filter on Camera 2s iso200_resize.jpg


-D

#6 colinbm

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Posted 23 February 2015 - 04:13

Good comparisons Damon, excellent test.
Col