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Hello from France

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#1 FL_96

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Posted 23 May 2021 - 13:56

Hello everyone,

First my apologies if I feel a bit formal, English is not my native language and self introduction is quite difficult sometimes.
After knowing this site since 2013-2014 I've finally done the move to register, and thanks the moderator for accepting my demand.

In a few words I am a 25 years old French. I have been into Infrared photography for quite some time now, and did few excursions into the Ultraviolet range. Those latter started with an old compact camera (canon powershot s50) with a B&W403 filter, then a few years later with the same filter combined with a Kolari Hot mirror on an old un-modified Nikon D100, with sometimes good results. I currently own a Full Spectrum Canon 6D and a Two Spectrum Fuji X-m1, both converted by Kolari Vision, as well as some vintage lenses, and search for advice regarding the choice of an interesting UV-pass filter or combination of filters for artistic/aesthetic reflected ultraviolet imaging.

I also wanted to thanks the members of this forum for the massive amount of useful knowledge and experiences about gear and technical aspects, and really enjoy seeing others experiments like those done with IRG or Aerochrome approach as they are quite difficult to refine and stabilize with regards to the lighting conditions.

Looking forward to resume invisible photography soon and discuss some technical knowledge :)

#2 nfoto

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Posted 23 May 2021 - 14:53

Hi and welcome to the UVP community. I do hope you interactions will be helpful and stimulating for all parties involved.

As to language, many UVP members (yours truly included) do not have English as their mother tongue. That doesn't prevent them from posting frequently :smile:, thus you should have no fear.

#3 dabateman

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Posted 23 May 2021 - 21:21

Welcome I write broken English as you may have read. I make far too many mistakes for someone speaking as long as I have. So don't worry. My French is now horrible as I haven't practiced in 20 years.

Feel free to ask any questions. I really have to get back photographing and share some of my crazy experiments. I have been building too many things like a UVC microscope, UVC 3D lenses and playing with odd filters.
My Nikon DF with the AF 1.7 teleconverter and Loawa 12mm lens has been fun though. Only visible light but excellent close up and nearly 1:1 with the AF teleconverter capable minimum focus distance.

Oh I did recently get a Chinese dichoic filter targeting 365nm as narrow band pass filter. I wouldn't recommend it. It leaks into visible and IR. It only works for UV if you stack it with 2mm U340. So filters are mostly best as they have always been.
The expense Baader venus u filter which is a dichoic filter or 2mm S8612 stacked with either U360/Ug1 or U340/Ug11.
For lenses that don't go deep into UV than a BG39 can work with even a ZWB2 filter as your lens would see the UV depth of the better filter combination any ways.

But than are you buy filters for the future or for what you currently have.

Edited by dabateman, 23 May 2021 - 21:27.


#4 FL_96

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Posted 24 May 2021 - 07:49

Thank you for your kind welcome :smile: .

Currently my biggest troubles are for choosing a filter which can bring unusual look to ultraviolet while staying truly uv (no infrared leakage). The work of O. Holovachov with deep blue flowers and yellow/white uv reflective patterns has been what made me think there is a strong potential aesthetically speaking in ultraviolet. I purchased quite recently an EL Nikkor 105mm (old metal version), which is so far the best one I have for the task (I have two copies of 80mm F/5.6 but one is the newer and damaged with fungus and oil tears inside, the second is the old one in better condition but hazy). I also have three optomax/prinzgalaxy brand lenses, one of them in good condition but suffering a light leak inside, all of them in the older design with protruding rear and smaller front element.

For filters I own a B+W 403 stacked to a Kolari hot mirror 1st generation. While it works properly on an old unmodified DSLR, it is not enough with a full spectrum camera, hence my interrogations regarding a new filter for uv or a stack one. I was targeting the Primalucelab-U one but am not sure about its current manufacturing, nor the mounting as it seems non-standard. Alternatively I'm considering the Straight-Edge U one or the kolari-U.

UVC experiments are very impressive (it sounds like going into the unknown), but need specific tools and precautions.

If you are interested I do some IRG/Aercochrome like infrared imaging (by experience Canon camera give better results compared to Fuji, while at 720nm Fuji takes a bit more advantage)

I also consider exploring the other extrema of the spectrum seen by the sensor. Is it worth trying to go 1000nm and slightly beyond (I've recently seen some experiments here showing interesting differences) ?

Here is a shot I did 3 years ago under uv with an unconverted Nikon D100 + EL Nikkor 50 mm F/4, mounted on helicoid focusing tube, with the stack mentioned above. I've observed that the sensor seems to be aging as there are some variance deviation appearing near the frame when saturation is enhanced :

Attached Images

  • Attached Image: DSC_0137 - Copie.jpg

Edited by FL_96, 24 May 2021 - 08:29.


#5 UlfW

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Posted 24 May 2021 - 08:48

View PostFL_96, on 24 May 2021 - 07:49, said:

Thank you for your kind welcome :smile: .

Currently my biggest troubles are for choosing a filter which can bring unusual look to ultraviolet while staying truly uv (no infrared leakage). The work of O. Holovachov with deep blue flowers and yelllow/white uv reflective patterns has been what made e think there is
To get rid of any IR-leakage a stack with a 2mm thick Shott S8612 is the best way.
That filter has enough IR attenuation to get an OD of 4 or better, when combined with almost all other filters.

You often get >OD5 (10^-5) in transmission where the second IR-peak is for UG1 and UG11.
The Baader U filter is quite expensive and give slightly less attenuation, even if it often can be enough.

My favourite stacks for UV are all based on a S8612, 2mm. I use that filter with U-360 2mm, UG1 1mm and UG2A 2mm.
The S8612 is also usable for different BUG-stacks,

The down slope of the transmission near 400nm for these combinations get closer and closer to, and then slightly beyond 400nm.
If you are really anal about UV only the UG2A is not really by the book, but the images still show UV-dark deep black floral signatures where they are supposed to be.

The colours obtained from the three stacks can be divided into how UV-yellow flowers look and how UV-blue flowers look.
  • The UV-yellow flowers get a slightly more saturated palette with the filter going slightly beyond 400nm (UG2A), as the total width of wavelengths passing that filter is the most wide.
  • The UV-blue flowers get a bigger colour change, ranging from dark violet, (U-360), changing towards a more pastel blue colour with UG2A. https://www.ultravio...attach_id=16425
The UG11 gives almost the same result as the U-360, but with longer exposure time.

The lenses the are usable for UV-photography mostly have small front lens elements and I think that 52mm diameter is a good alternative, especially as that is a dimension with most available filter types.

Hope these thoughts can be of some use



The Primaluce U is not something I can recommend as the performance is very variable between iterations.
The one I got leaks IR very much while the one Enrico show on his website is better.

In general I would recommend going for absorbance type filters as they give a better control of IR-leakage and no problem with the potential colour shift in the corners for wider lenses.
The Straight-Edge U is an interesting filter that I use as a complement, especially for flowers with blue UV-colour. That filter gives an interesting pale destaurated blue colour, even paler than UG2A 2mm

Edited by UlfW, 24 May 2021 - 09:07.

Ulf Wilhelmson
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#6 dabateman

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Posted 24 May 2021 - 10:54

Yes I have to remember not to talk about UVC to newish members. Expensive, extremely dangerous and requires a lot of care.

Ulf covered most of what I would say for filters. The best IR blocking filter is a S8612 filter. You might get lucky with s cheap Chinese BG39 equivalent or not and need to buy a S8612 anyway. So best to just buy one.
Then look at the other curves and get a Uv filter you would be happy with.

#7 UlfW

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Posted 24 May 2021 - 12:17

Here are some example images for different filter stacks:
The images are reasonably well white balanced and with similar exposure.
Identical settings beside that for all four images, directly from the Raw Viewer

U-360 2mm + S8612, 2mm
Attached Image: Screen Shot 2021-05-24 at 14.03.45.png

UG1 1mm + S8612, 2mm
Attached Image: Screen Shot 2021-05-24 at 14.04.09.png

UG2A 2mm + S8612, 2mm
Attached Image: Screen Shot 2021-05-24 at 14.04.30.png

StraightEdge U rev. 3
Attached Image: Screen Shot 2021-05-24 at 14.07.13.png

Edited by UlfW, 24 May 2021 - 12:21.

Ulf Wilhelmson
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#8 FL_96

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Posted 24 May 2021 - 18:07

UlfW, Dabateman, thank you a lot for your kind and very detailed answer, they will be really useful for determining which filter or stack to use for aesthetic ultraviolet photography. By looking at the examples, the UG2A 2mm + S8612 2mm stack seems to be my preference from the examples, though I also like the pale de-saturated look from the Straight Edge U III. It narrows much more the choice. Definitely with a 52mm diameter. The UG2A looks closest to the results obtained with B&W403 + Kolari Hot Mirror + Nikon D100 internal Hot Mirror.

#9 UlfW

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Posted 24 May 2021 - 18:24

Be aware of that some will say that a S8612 + UG2A, both 2mm is not a real proper UV pass stack as it also passes a tiny bit of visual deep purple.
IMHO I think it would be extremely difficult to se any difference of the pure colours of 395nm and 405nm.

The image made with the U-360 has a palette almost identical to what you would get with a Baader U.

As long as you go with a stack approach based on a S8612 2mm you can eventually and gradually expand your collection of filters and explore may different types of interesting imaging.
Ulf Wilhelmson
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#10 FL_96

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Posted 30 May 2021 - 10:33

Hello, after some reflections, I think I will go for the Straight Edge U filter. However I will also buy the S8612 when available in 52mm size as it will probably give similar results to UG1 - UG2A with B&W 403.