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A Group of Rudbeckia

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#1 Cadmium

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Posted 27 July 2020 - 01:50

Again, the rudbeckia flower, this time a group.
D7000 UVIR, Kuribayashi 35mm f/3.5 lens.

Visual (Schott BG38).
Attached Image: Rudbeckias_Visual_Schott_BG38_1280.jpg

UV (Hoya U-360 2mm + S8612 2mm).
Attached Image: Rudbeckias_UV_Hoya_U360_2mm_x_Schott_S8612_2mm_1280.jpg

BUG 5 (Schott UG5 1.5mm + S8612 2mm), UV+Blue+Green mix, 'bee vision', 'BUG'.
Attached Image: Rudbeckias_UG5_1p5_x_S8612_2mm_Stack_1280.jpg

BUG 3 (Schott BG3 1.5mm + S8612 2mm), UV+Blue+Green mix, 'BUG'.
Attached Image: BG3_1p5mm_x_S8612_2mm_1280.jpg

UV Film Simulation, using BUG 5 (Schott UG5 1.5mm + S8612 2mm), channel mixed.
Attached Image: Rudbeckias_UV_Film_Sim_BUG_5_1280.jpg

IR (Schott RG695).
Attached Image: Rudbeckias_IR_Schott_RG695_1280.jpg

All six shots from above compared.
Attached Image: Rudbeckias_All_Stack_6_Shots_1280.jpg

Edited by Cadmium, 27 July 2020 - 02:01.


#2 Stefano

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Posted 27 July 2020 - 03:47

Very nice Steve.

#3 Cadmium

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Posted 27 July 2020 - 03:54

Stefano, Thank you! :smile:

#4 dabateman

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Posted 27 July 2020 - 05:26

I like your bug5 switched. Looks similar to Birna's famous shot.

#5 GaryR

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Posted 27 July 2020 - 12:21

That UG5 is sooo nice! Is there a big difference in visual results, between a 1.5 and 2mm thick UG5 ?
The UV film sim version is quite beautiful.

#6 Cadmium

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Posted 27 July 2020 - 22:41

David, Thanks! :-) Yes, I like the UG5/U-330 stacks.

Gary, That is really an excellent question. I should document that next time I photograph a yellow flower.
Many years back, 'we' (a few) decided that the 1.5mm thick was the best, because the green was more 'pronounced'.
Basically the green looks darker when using 2mm. I have examples, but not true comparisons.
Originally I started by using 2mm, it works, but I think the 1.5mm looks better.
1mm thick will also include red in the mix, but still shows the UV/Green pattern. When using 1mm UG5/U-330 you will see red flowers as red, but with 1.5mm and 2mm thick UG5/U-330 the red flowers will look black or gray.
I will make a comparison example of UG5/U-330 1.5mm vs 2mm soon.
Thanks! :smile:

Edited by Cadmium, 27 July 2020 - 22:43.


#7 GaryR

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Posted 28 July 2020 - 12:55

Thanks Steve. A 1.5/2mm comparison would be great.
btw. The Hoya U-330 seems to cost less than the UG5. Is there any benefit that the UG5, would have over the U-330?

#8 Cadmium

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Posted 29 July 2020 - 01:02

Hi Gary, I didn't do the UG5 vs U-330 comparison today, but those should have the same results at the same thickness. I will do a 1.5mm thick comparison soon.
Today I compared UG5, 1mm, 1.5mm, and 2mm. Two different flower types.
In the shade. Direct sun will have slightly different results, which I show an example of using the 2mm thickness.
I still prefer the 1.5mm thick in shade or sun.
The 1mm thickness with also show red, as with the older comparison lower down. The 1.5mm and 2mm will not transmits red.
Nikon D7000 UVIR, UV-Nikkor 105mm.

UG5 1mm, 1.5mm, 2mm, + S8612 2mm stacks compared (shade), rudbeckia flowers.
Attached Image: Rudbeckia_UG5_1mm_1p5mm_2mm_stacks.jpg

Visual (Schott BG38), and UG5 1mm, 1.5mm, 2mm, + S8612 2mm stacks compared (shade), yellow flower.
Attached Image: Small_Yellow_Flower_Visual_BG38_UG5_1mm_1p5mm_2mm_stacks.jpg

UG5 2mm + S8612 2mm (from above), shade vs direct sun.
Attached Image: UG5_2mm_shade_vs_sun.jpg

UG5 1mm vs 1.5/2mm stack (not sure if I was using 1.5mm or 2mm stack in this comparison), direct sun.
Attached Image: Rudbeckia_UG5_1mm_and_2mm.jpg

How about a handy graph comparison? You betcha! :smile:
Attached Image: UG5_1mm_1p5mm_2mm_x_S8612_2mm_stacks_compared.jpg

Edited by Cadmium, 29 July 2020 - 01:28.


#9 UlfW

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Posted 29 July 2020 - 10:24

The last post is by far the best and most informative one I have seen.
Well done Steve!

The image-pair with shade vs direct sun is specially interesting for me.
It show a phenomenon I have been struggling with quite some time, with this type of stacks.
It has been difficult to replicate Steves results directly.

The image in the shade has been exposed to a UV/VIS-ratio with more UV, making the green darker.
That sounds illogical at first.

Naturally there is more absolute UV-power in direct sunlight than in the shade!
However the shade-image is illuminated only by the sky, blue (+UV), without any of the warmer colours directly from the sun.
that leads to an UV/VIS-ratio with more UV.

These type images are very sensitive to both differences in sensor sensitivity and light source for the UV/VIS-ratio.
They are also more difficult to white-balance as the raw-files are extremely blue.

I have sometimes had problems getting meaningful green patterns with UG5 1.5mm and thinner and then only the 2mm worked.
For my location rather high up on the globe, latitude 55.5° north, in early spring, in March, when flowers start to bloom the UV/VIS-ratio is low, especially some hours before or after noon.

With my UV-flashes with good UV/VIS-ratio the effect is opposite. Then the 2mm give a green way too dark.

Edited by UlfW, 30 July 2020 - 07:59.

Ulf Wilhelmson
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#10 GaryR

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Posted 29 July 2020 - 18:30

Thanks Steve, Great presentation! Easy to see the color differences...1.5mm is a nice balance indeed. Interesting to see the visual range differences in the diabatic chart, and direct sun comparison. Very beautiful imagery!

#11 UlfW

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Posted 30 July 2020 - 08:08

Depending on if the illumination situation changes much, it might be useful to have more than one thickness of these UG5/U-330-filters.
I have 1mm, 1.5mm and 2mm of Schott/Hoya-glass, and find all of them useable from time to time.

With my Canon 60D and UG5, 1mm, in sunlight I could not get as much red as Steve do, with his Nikon.
This can both depend on the characteristics of the available light and camera type.

Edited by UlfW, 30 July 2020 - 08:10.

Ulf Wilhelmson
Curious and trying to see the invisible.

#12 Cadmium

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Posted 31 July 2020 - 05:57

Here are two tests, comparing U-330 1mm vs UG5 1mm and U-330 1.5mm vs UG5 1.5mm.

Visual (Schott BG38).
Attached Image: Visual_Checker_Red_Flower_Rudbeckias_1280.jpg

Hoya U-330 1mm + Schott S8612 2mm (left) vs Schott UG5 1mm + Schott S8612 2mm (right).
Attached Image: UG5_1mm_vs_U330_1mm_checker_red_flower_rudbeckias_1280w.jpg

Hoya U-330 1.5mm + Schott S8612 2mm (left) vs Schott UG5 1.5mm + Schott S8612 2mm (right).
Attached Image: UG5_1p5mm_vs_U330_1p5mm_checker_red_flower_rudbeckias_1280w.jpg

1.5mm stacks.
Attached Image: U330_1p5_x_S8612_2mm_vs_UG5_1p5mm_x_S612_2mm.jpg

Added. 1mm stacks.
Attached Image: U330_1mm_x_S8612_2mm_vs_UG5_1mm_x_S612_2mm.jpg

Edited by Cadmium, 31 July 2020 - 20:49.


#13 dabateman

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Posted 31 July 2020 - 11:07

This is a great comparison.
If the lighting is the same, than I do see a difference between the 1.5mm samples with the top right flower being darker with U330. I have 1.5mm U330 and 1mm ug5 and haven't gotten around to this test. Great.

#14 GaryR

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Posted 31 July 2020 - 17:35

Excellent comparison. Thanks Steve!

#15 Andrea B.

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Posted 31 July 2020 - 20:35

For Hoya U-330 x 1.5 mm + S8612 x 2.0 mm
and Schott UG5 x 1.5 mm + S8612 x 2.0 mm
see also
https://www.ultravio...ers-3-examples/
Andrea G. Blum
Often found hanging out with flowers & bees.

#16 Cadmium

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Posted 31 July 2020 - 20:45

Ooo, Andrea, I like your BUG3 shot there, great example of that.
By the way, I added the UG5 and U-330 1mm stack graphs above.

#17 bobfriedman

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Posted 01 August 2020 - 21:57

really nice set of comparison data, excellently photographed too, by the way.

#18 Cadmium

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Posted 02 August 2020 - 03:48

Bob, Thanks! :smile:

Edited by Cadmium, 02 August 2020 - 03:48.