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BG3 with unconverted Nikon D600

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#1 Ural

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Posted 15 October 2020 - 21:25

Today I received BG3 (2mm) and decided to test what happens if I use it with unconverted Nikon D600. The result is not quite UV photography so I decided to post it in UV/IR experiences, maybe someone will be interesting how such combination would look like (everything is blue) and what it is possible to do with it. I found such combination can be used in art by applying some base tone curve adjustments in DNG profile editor and then adjusting exposure/temp/tint/blue colour in Lightroom.
This inspired me to dismantle my camera today and hopefully it will be ok after removing UV/IR cut filter.

Here is original file.
Attached Image: DSC_3903 s.jpg

Here is how the base tone curve looks like in DNG profile editor.
Attached Image: DNG curve s.jpg

Here are some tweaking results in Lightroom
Attached Image: DSC_3904-2-2 s.jpg

Attached Image: DSC_3904 s.jpg

Attached Image: DSC_3904-3 s.jpg

+ white balancing in Photo Ninja
Attached Image: PN s.jpg

Edited by Ural, 15 October 2020 - 21:31.


#2 Stefano

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Posted 15 October 2020 - 21:52

You unlock BG3's full potential with a full-spectrum camera. Stacking it with some S8612 and GG longpass filter (such as GG455) could be useful to make a blue bandpass filter, or a violet+blue bandpass or, even broader (without the GG filter) a UV+violet+blue bandpass. The combinations are almost endless, you can make your recipe to your taste.

I like the image you obtained. It is somewhat similar to my first UV ones.

#3 Cadmium

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Posted 15 October 2020 - 22:15

Use a full spectrum camera, use BG3 alone or with KG3 for stronger color.

#4 colinbm

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Posted 15 October 2020 - 23:58

Nice artistic results there Ural.
Good luck with your conversion & your entry into UVA.

#5 Cadmium

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Posted 16 October 2020 - 04:37

Ural, Here are some examples of BG3 alone, and three other BG3 stacks (using a full spectrum camera), the sky's the limit... all dependent on actual white balance.

Attached Image: BG3_2mm_stacks_photos_1280w.jpg

Attached Image: BG3_and_some_stacks.jpg

#6 Ural

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Posted 16 October 2020 - 13:42

View PostStefano, on 15 October 2020 - 21:52, said:

You unlock BG3's full potential with a full-spectrum camera. Stacking it with some S8612 and GG longpass filter (such as GG455) could be useful to make a blue bandpass filter, or a violet+blue bandpass or, even broader (without the GG filter) a UV+violet+blue bandpass. The combinations are almost endless, you can make your recipe to your taste.

I like the image you obtained. It is somewhat similar to my first UV ones.

Thank you Stefano! It would be great if you could share some examples of using BG3, especially interesting combination BG3 and GG455. Thank you!

#7 Stefano

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Posted 16 October 2020 - 13:55

View PostUral, on 16 October 2020 - 13:42, said:

Thank you Stefano! It would be great if you could share some examples of using BG3, especially interesting combination BG3 and GG455. Thank you!
At the moment I don't have any BG3 filter, but surely in the future I will get one and share my results.

If you download the Schott 2017 filter program you can experiment with stacks and see the transmission graphs, like the ones Steve (Cadmium) posted above (although I think he is using the older version of the program).

#8 Ural

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Posted 16 October 2020 - 14:00

View PostCadmium, on 16 October 2020 - 04:37, said:

Ural, Here are some examples of BG3 alone, and three other BG3 stacks (using a full spectrum camera), the sky's the limit... all dependent on actual white balance.

Attachment BG3_2mm_stacks_photos_1280w.jpg

Attachment BG3_and_some_stacks.jpg

Thank you Cadmium,
BG3 (2mm) + KG3 (2mm) looks interesting. What if I will use BG3 (2mm) + KG5 (3mm) or BG3 (2mm) + BG39 (1mm)? Will be trees red like using U-410?

#9 Ural

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Posted 16 October 2020 - 14:07

Stefano, Colinbm, thank you for you replies!

#10 Cadmium

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Posted 16 October 2020 - 22:03

Do you mean B-410 (no such thing as U-410)?
I think with optimized full frame white balance you will tend to get orange foliage instead of red, even when stacked, because B-410 transmits a good amount of visual green.
I have posted examples on here of B-410 + KG3, etc.. No matter what you stack it with, it has a lot of visual green and some visual red, which is not an optimal mix for getting red foliage.
You want to block the visual green + red, and replace it with 700nm range IR (which has stronger Bayer red content than does higher range IR). Best I have found is Lee/Rosco 729 + KG3.

Your two stacks, other than the slightly unusual thicknesses of the KG5 and BG39, are in the same progression range as the example I posted above.
The KG5 stack is above, and the BG39 stack is below the BG38 stack I showed. So you can imagine the look of each, based on the example shot I show.
Sky would be more or less blue saturation, and foliage shifts between yellowish and reddish, depending on how much suppression is used
I am pretty sure that the KG5 3mm stack would be more red than the KG3 2mm stack I show, but probably not exactly red.
KG5 3mm might be a special order, and BG39 1mm would be somewhat special also,
and would be best to use S8612 1mm because the suppression of those two are the same, and S8612 is much more versatile than BG39.

Attached Image: BG3_2mm_x_KG5_3mm_vs_BG3_2mm_x_BG39_1mm_stacks.jpg

Schott BG3 vs Hoya B-410
Attached Image: B410_BG3.jpg

#729 had NO visual red, no IR until 750nm.
Attached Image: Lee_Scuba_Blue_729_wider_graph.jpg

Edited by Cadmium, 16 October 2020 - 22:13.


#11 Ural

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Posted 17 October 2020 - 16:29

View PostCadmium, on 16 October 2020 - 22:03, said:

I think with optimized full frame white balance you will tend to get orange foliage instead of red, even when stacked, because B-410 transmits a good amount of visual green.

Thank you, Steve, for information and correction, B-410.
Yesterday I converted the camera, everything works, and everything is purple or read in photos. Now I have much more questions :-) After a few shots of roses with BG3, I notice that foliage is yellow.
I am trying to understand how to read graphs and why with BG3 filter foliage is yellow and it is red with B-410. If we look at the graph BG3 transmits UV, Blue, a bit green, a bit Red and IR. Is it true that we get yellow foliage because we replaced yellow and green with IR (which foliage radiates) when white balancing in PC? So, foliage that was yellow, and green became, just yellow, blue skies remained the same blue. But why is foliage yellow, why not green, and what is the role of UV in this colour conversion?
With B-410 we have UV, Blue, Green, Yellow, IR, how we get red foliage with this filter? Is it because we replace red with IR when white balancing? But why foliage is red instead of staying green and yellow?
Sorry for so many questions, I am really interested in these details after conversion.
Steve, may I also ask which software I can use to build such informative graphs? I recently installed Schott excel file, but it does not have Hoya’s filters such as B-410.
Thank you for advice on S8612!

PS.
Those roses (BG3, 2mm). My first UV/IR digital photo with converted camera (source of light - only LED lamp).
Attached Image: _DSC4301 s.jpg

Edited by Ural, 17 October 2020 - 17:05.


#12 Stefano

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Posted 17 October 2020 - 18:33

View PostUral, on 17 October 2020 - 16:29, said:

I recently installed Schott excel file, but it does not have Hoya’s filters such as B-410.
Hoya filters are not already present, you have to insert their data yourself.

#13 Cadmium

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Posted 17 October 2020 - 22:06

Ural, Those are very good questions, I am impressed with how your thinking.
It is hard for me to 'wrap my mind around' some of these transmission plots vs photo results sometimes. It makes me think.
It is a combination of things that are sometimes a little hard to stack together in the mind, and make sense of compared to the photo results.
The BG3 yellow/brown foliage doesn't come from the visual range colors (orange/yellow/red), except for a small amount from the upper 600nm deep red visual range.
Instead, the yellow/brown is mostly coming from the uneven Bayer filters transmission of the Infrared above 700nm and above.
That is why when BG3 is stacked with KG3 (for example) the yellow becomes more red, because the lower IR range (700nm to 830/850nm) transmits stronger through the RED Bayer filters.
With dual band filters (UV+IR), the usual tendency is for UV to look blue. For example, UG1/U-360 will have violet/blue skies with mostly white foliage (when white balanced on the foliage).
The same tendency happens with other dualband filters that include UV, it is mostly overpowered by the other ranges (visual/IR), and blue is coming from mostly the upper UV as seen through the Bayer filters.
About B-410 being 'red'. Personally, I don't get red, I get orange. It is a more delineated and differentiated orange when I stack B-410 with KG3 (for example), but still just orange, although the KG3 cleans up the whites and grays,
see example photo below.
I have seen more reddish B-410 examples (un-stacked even), but that may have to do with white balance or camera, etc.?
I am not understanding the redder look of the B-410 at the moment either.
Do you have B-410?
If so, then the best test comparison that might enlighten the thinking is B-410 compared to BG3, both alone, neither stacked, same white balance.
The white balance my not be optimal for each, or even for either, but given the same white balance it should tend to help understand the difference in transmission of the filter x transmission of the Bayer filters combined. Sorry, I don't have such an example that I am able to find right now.

Yes, the Schott filter transmission program. Hoya 'internal' transmission data (Ti, not T) has to be entered into the Schott program manually or by import from Hoya filter program export, if supplied for given glass type.

Attached Image: B410_alone_and_with_KG3_1280.jpg

Edited by Cadmium, 17 October 2020 - 22:19.


#14 Cadmium

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Posted 17 October 2020 - 22:16

Off topic a bit, but I have been thinking about testing this stack below for a while, I just haven't done it because it is so ridiculously thick.
Hoya B-410 10mm thick (even 12mm maybe) + KG3 2mm, this has a somewhat similar transmission plot as the #729 + KG3 2mm stack, but all glass.
I have used the U-340 8mm thick filter, and it seems sharp and good to me, so I don't know how well the B-410 10mm would work,
but it seems like an interesting test. It should or might work like the 729 stack, hard to say for sure how red it would be.
Like I said, that is a lot of B-410, FIVE 2mm thick B-410 filters, or two 4mm and one 2mm (three filters stacked/glued).
Free sunny day list.

Here is a graph for the 10mm + 2mm stack. Arguably, B-410 8mm might work? Would get more upper 500nm range visual.
Attached Image: Hoya_B410_10mm_x_KG3_2mm_Stack_vs_729_x_KG3_Stack.jpg

Edited by Cadmium, 18 October 2020 - 09:45.


#15 Ural

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Posted 20 October 2020 - 19:03

View PostCadmium, on 17 October 2020 - 22:06, said:

It is hard for me to 'wrap my mind around' some of these transmission plots vs photo results sometimes. It makes me think.
Attachment B410_alone_and_with_KG3_1280.jpg

Thank you Steve. I think the element of unpredictability that is why people are interested in ultraviolet photography. It's always interesting to experiment with different filters and then see what happens. Hopefully, B-410 will come in a week or two and then I can compare BG3 and B-410 filters and stack them both and look what happens :-)
I just imported B-410 transmission data in Schott program and compared with yours graph, it looks similar. Thank you and thanks Stefano.
Indeed thick B-410 + KG3 and Lee729 + KG3 graphs looks very similar. I found post with U-340 8mm thick and Lee729. Perhaps B-410 10mm thick + KG3 2mm will make orange (because there will be less IR) everything that was green and yellow, and cherry red what was red, skies should be blue because IR will be blocked by KG. It will be interesting to see the result.

BG3+B-410, there should be less red
Attached Image: BG3+B-410.jpg

Edited by Ural, 20 October 2020 - 19:07.