• Ultraviolet Photography
  •  

UVIVF Possible Visible Light Leak?

Fluorescence White Balance
57 replies to this topic

#21 Cadmium

    Member

  • Members+G
  • 3,691 posts

Posted 22 February 2019 - 18:29

You mean U-340? I am not using U-360 on the torch.
Regardless, yes, you wan't the barrier lens filter to cu at or above 400nm, 420nm to 435nm is quite common also.
So if the Firecrest cuts at 370, then I would not use it for blocking UV on the lens.

Yes, the Firecrest UV/IR MC may have a lower cutoff, didn't know that.
The Friecrest UV/IR MC, UV 400 MC, and Baader UV/IR-Cut all look like they transmit some UV about the same amount when doing the same test directly with my full spectrum camera.

The tests I did above were done using a stock D610, with a 18-55mm VR lens, both of which cut at least some UV to start with.
Those tests were only to show that the U-340 filter on the torch cuts all visible light and also transmits UV (thus the fluorescence).

Edited by Cadmium, 22 February 2019 - 18:44.


#22 UlfW

    Ulf W

  • Members+G
  • 1,110 posts
  • Location: Sweden, Malmö

Posted 22 February 2019 - 19:53

View PostCadmium, on 22 February 2019 - 18:29, said:

You mean U-340? I am not using U-360 on the torch.

Those tests were only to show that the U-340 filter on the torch cuts all visible light and also transmits UV (thus the fluorescence).

Correct, it was a typo, I ment U-340.

Well done test. I saw that it wasn't about the lens filter, but later you said that either one could be OK, and I think that is wrong.

I think the reason for the confusion is that at the Friecrest website looks like they have four different filters:

UV
UV/IR MC,
UV/IR 370 MC
UV/IR 400 MC

I think the UV/IR MC designation is for the pair
UV/IR 370 MC
UV/IR 400 MC
and that there are three types, not four.
Ulf Wilhelmson
Curious and trying to see the invisible.

#23 dabateman

    Da Bateman

  • Members+G
  • 1,976 posts
  • Location: Maryland

Posted 22 February 2019 - 19:53

Cadmium,
All the tickets were sold out. I am glad I did get to see it in reruns though.

Do you have both Firecrest filters? I remember there was some confusion on which one they sent you.

#24 Cadmium

    Member

  • Members+G
  • 3,691 posts

Posted 22 February 2019 - 21:06

Firecrest has 4, only one cuts UV+IR, the other three cut UV only (in various amounts).

"Firecrest UV filters come in four variations:
UV Multicoated offers basic UV and lens protection.
UV 370nm is a premium filter with a defined UV cut at 370nm.
UV 400nm offers the maximum UV reduction for shooting high altitudes and snow. Schott Superwite glass makes this the ultimate UV filter.
UV IR Cut is a specialty filter that reduces ultraviolet and infrared."

Scroll down to the bottom:
https://www.formatt-...ircular-filters

I have these two:
UV 400 MC (52mm)
UV IR MC (52mm)

I am not clear what the cutoff point is for the UV IR MC filter.
Let me know if you find that info.

Edited by Cadmium, 22 February 2019 - 21:09.


#25 JMC

    Member

  • Members+G
  • 1,041 posts
  • Location: London, UK

Posted 22 February 2019 - 22:25

Steve, have you seen any actual spectra for these UV filters? I'm intrigued by just how sharp their cut off really is.
Jonathan M. Crowther

http://jmcscientificconsulting.com

#26 Cadmium

    Member

  • Members+G
  • 3,691 posts

Posted 22 February 2019 - 22:26

I called their USA branch, twice, no answer, left a message, no word, so I have no idea what the UV/Visual ~400nm~ cutoff point is for their UV IR MC filter. I can't find the info about that anywhere.
So... If you missed the first show, your ticket is good for the second show.

This is my test, shooting down from above at a Convoy S2+ filtered with U-340 2mm.
Same exposure, settings, and white balance for all shots.
This might lead me to believe that the UV IR MC has better UV cutoff than the UV 400 MC, and that the Baader UV/IR-Cut has better UV cutoff than either of the Firecrest filters.
However, it can be a sticky wicket or problematic and deceptive to shoot tests of LED's, they can be intensively powerful, intensive enough to burn through strong OD blocking and cutoff, even into ranges that are not associated with the LED.
So I can't say for sure if what we see is UV or even IR, because I think I might be able to do about the same thing with an IR longpass filter.
For what it's worth, here is a comparison.
I think Firecrest needs graphs. Maybe their UV400 isn't exactly 400nm, if we go by this comparison.
By the way, the bright violet/blue/white circle in the background is the paper under the Convoy, fluorescing from the reflected UV off the front of the camera lens filters, which was always about the same with each filter, And that might be another aspect to consider, the UV reflected back at the front of the Convoy, but maybe some other time...

Attached Image: Firecrest_Test_UV_Cut.jpg

#27 cdhgamer

    Member

  • Members
  • 24 posts

Posted 23 February 2019 - 01:21

Steve or anyone else, have you ever had to repair a Convoy S2+? I switched out the battery last night, and now it won't turn on with any of my 4 batteries.

Edit: Disregard, the center shaft where the battery is got flipped around, didn't realize the direction mattered.

Edited by cdhgamer, 23 February 2019 - 01:27.


#28 Cadmium

    Member

  • Members+G
  • 3,691 posts

Posted 23 February 2019 - 02:56

You're right, never run into that before, guess that can happen if you remove both ends at the same time.
Good to know.

#29 JMC

    Member

  • Members+G
  • 1,041 posts
  • Location: London, UK

Posted 23 February 2019 - 14:57

Ok thanks Steve, and I fully I agree we need charts for these Firecrest filters. I have the feeling it isn't going to be a nice vertical drop at 400nm for their 400 one, and like wise for the 370 one. If I end up getting any I will of course post my findings.

EDIT - ordered one of the 400nm UV filters, so will see what it's like when it gets here.

Edited by JMC, 23 February 2019 - 15:54.

Jonathan M. Crowther

http://jmcscientificconsulting.com

#30 cdhgamer

    Member

  • Members
  • 24 posts

Posted 24 February 2019 - 07:10

Sorry to revive the topic again, but I shot more photos last night, and the colors just aren't matching up with any sort of white balancing I do to what I visually see, which is a bit confusing and frustrating.

Here is the shot with daylight white balance.

Attached Image: DSC_3995-Edit.jpg

Here's an edit that is much closer to what I visually see, although the stamen should be red from chlorophyll, and I can't really get a white balance to reflect that aspect. This is at Temp - 50,000, and Tint - 50

Attached Image: DSC_3995.jpg

I'm really at a loss for why these photos seem to be so blown out in the blue/purple spectrum if that's not what I'm visually seeing. I'm also still confused why I'm able to shoot at such a low shutter speed. I'm stopping down for the depth of field that I want, but if I opened the lens I'm using wide, I'd be shooting at 1/8 s at ISO 500, shouldn't it be closer to 10 to 15 seconds? I apologize if these are bad questions at all. I'll attach a photo of the flower in normal light with a correct white balance below too.


Attached Image: DSC_3997-Edit.jpg

Edited by cdhgamer, 24 February 2019 - 07:11.


#31 Cadmium

    Member

  • Members+G
  • 3,691 posts

Posted 24 February 2019 - 07:55

OK, you are using a D810, stock camera, right? Not converted.
Any UV blocking filter on the lens at all?
If you are seeing the red then I don't know exactly why the red is absent in your photo.
I don't know the advised way to white balance for UVIVF, like I said, I just try to match it up with what I see, but you are seeing the red.
You might want to ask Dave or Mark, they both do UVIVF on a fairly regular basis and seem to be pretty precise with their captures.
I don't think any usual white balance setting in the camera is going to work that well, to get close you will probably need to do a custom white balance, and the fastest way to play around with that would be from RAW, like with NX-D or Ninja.
I also have a D810 stock, but I have never used it for UVIVF so far.
I would think that if you are seeing red, then it should show up with a stock camera if the lens is not filtered.

#32 cdhgamer

    Member

  • Members
  • 24 posts

Posted 24 February 2019 - 08:32

View PostCadmium, on 24 February 2019 - 07:55, said:

OK, you are using a D810, stock camera, right? Not converted.
Any UV blocking filter on the lens at all?
If you are seeing the red then I don't know exactly why the red is absent in your photo.
I don't know the advised way to white balance for UVIVF, like I said, I just try to match it up with what I see, but you are seeing the red.
You might want to ask Dave or Mark, they both do UVIVF on a fairly regular basis and seem to be pretty precise with their captures.
I don't think any usual white balance setting in the camera is going to work that well, to get close you will probably need to do a custom white balance, and the fastest way to play around with that would be from RAW, like with NX-D or Ninja.
I also have a D810 stock, but I have never used it for UVIVF so far.
I would think that if you are seeing red, then it should show up with a stock camera if the lens is not filtered.

Yep, my Nikon D810 is stock, and I also tested my D750 which is stock as well. I tried some other lens combos just incase my macro lens was somehow leaking more blue/purple than other lenses but they all seemed the same. And I have been shooting in RAW and messing with custom white balances in Lightroom, but I think it does have a more limited white balance compared to those programs doesn't it?

Some flowers do seem to be fluorescing somewhat close to what I can see visually, but it's seeming like any flower that fluoresces blue or purple for the most part, those colors are washing out reds/oranges, but not yellows.

What are Mark and Dave's usernames by the way?

Edited by cdhgamer, 24 February 2019 - 08:34.


#33 Andy Perrin

    Member

  • Members+G
  • 3,223 posts
  • Location: United States

Posted 24 February 2019 - 17:21

Quote

Yep, my Nikon D810 is stock, and I also tested my D750 which is stock as well. I tried some other lens combos just incase my macro lens was somehow leaking more blue/purple than other lenses but they all seemed the same. And I have been shooting in RAW and messing with custom white balances in Lightroom, but I think it does have a more limited white balance compared to those programs doesn't it?

Quote

Any UV blocking filter on the lens at all?
As Cadmium said, you need a FILTER on the lens to block UV. It sounds like the answer to his question here is "no" and that may be the issue. It's not about the lens, it's about not having a filter.

Edited by Andy Perrin, 24 February 2019 - 17:22.


#34 Cadmium

    Member

  • Members+G
  • 3,691 posts

Posted 24 February 2019 - 22:03

I was kind of asking in the reverse, because I was wondering if whatever UV/IR cut filter on the lens might be cutting off too much of the red...
My thinking is that if there camera is stock and there is no lens filter, then it should be recording visible red if seen by the eyes.
So I don't have any idea about that, given the scenario.
But a lens filter that blocks UV would be something to try/test, who knows.

#35 Cadmium

    Member

  • Members+G
  • 3,691 posts

Posted 24 February 2019 - 22:21

Try NX-D, I think it is free, I think it works with D810.
It doesn't have a very large white balance sample area, not like the Marquee in NX2, but it still works.
https://downloadcent...pture_NX-D.html

#36 cdhgamer

    Member

  • Members
  • 24 posts

Posted 25 February 2019 - 02:48

View PostAndy Perrin, on 24 February 2019 - 17:21, said:

As Cadmium said, you need a FILTER on the lens to block UV. It sounds like the answer to his question here is "no" and that may be the issue. It's not about the lens, it's about not having a filter.

Alright, thank you Andy, that's what I've been trying to figure out, I heard from various people that I don't "really need" it and I keep feeling like I should really get one but I was hearing conflicting things, or at least that's what I was taking from it, maybe I was misunderstanding some people

#37 Cadmium

    Member

  • Members+G
  • 3,691 posts

Posted 25 February 2019 - 04:06

Once again, I didn't mean to say you need a filter on the lens, I was kind of saying the opposite.
Since you are using a stock camera, and a non-UV friendly lens, then you may not be getting much UV to your sensor.
I see a huge difference in UV between shooting the Convoy with the full spectrum D7000 + the Kuribayashi UV friendly lens, and the D610 or D810 stock cameras with modern kit lenses.
I just now tried all of this.

Camera Sensor < (Internal UV/IR-Cut filter) < Lens < (UV blocking filter) < < < < < U-340 (visual blocking filter) < Convoy S2+ 365nm Nichia LED

Shooting head-on at the U-340/Convoy, I see very weak UV with the D810 and D610 using modern Nikon lenses.
Using the Kuri lens instead, I see more UV with the D810 and D610.
Shooting with the D7000-UV/IR with Kuri, I see a LOT of UV.

So, the lens has a lot to do with how much UV is getting to the sensor.
When I put the Firecrest UV IR MC on the kit lens the UV becomes almost undetectable using my stock cameras.
I do believe the UV IR ME cuts more UV at a higher nm than does their UV 400 MC filter, regardless of the numbers, but I am not saying either of those filters should be used for cutting UV,
there are others, but I am not saying you absolutely need it either, given your stock visual equipment.
On the other hand if someone is using a full spectrum camera they pretty much need to cut the UV at 400nm to 435nm.
I am not familiar with the Tokina 100 mm Macro f/2.8, but it looks pretty modern, so it probably doesn't transmit UV well, of course, a lot of lenses will transmit some UV, down to 380...more? Don't know, they are all different.
If I were you, I would first try white balancing with NX-D, it is made for Nikon, and it would be rather handy to have, and it is free I think still. Try that first.

Edited by Cadmium, 25 February 2019 - 04:08.


#38 UlfW

    Ulf W

  • Members+G
  • 1,110 posts
  • Location: Sweden, Malmö

Posted 25 February 2019 - 06:37

The problem might be a white balance issue, but also an uv leakage in the stock camera's internal filtering.
If white balancing fails the next step would be to put a suitable filter on the lens.

From the graph of the filter transmission it is clear that the D810's UV-blocking is done by a dichroic filter:
https://diglloyd.com...sion-curve.html

For normal photography this filtering is good enough as the sensor's UV-sensitivity is low too.
However the light levels from fluorescence are low and then it might not be enough.

Sometimes dichroic filter are not blocking that good in their reject bands.
We know that from earlier versions of the Baader U-filter.
That filter had an IR leakage causing problems for UV-photography with full spectrum cameras.

The small wiggle in the article about the transmission graph for the D810 near 400nm can be an indication that this filter too might leak a bit into the UV.
If the leakage exist and is strong enough it might allow enough UV-light to overwhelm the weak VIS-fluorescence.

The UV-blocking of modern lenses is not a main design issue when creating the coatings and no safe way to eliminate UV during fluorescence-photography.
They are optimised to transmit maximally and flat in the VIS and to do that the blocking can begin a bit into the UV-range.
Modern lenses are also often built with many lens elements causing an UV-cutoff, but that can sometimes give a cutoff further into the UV.
For UV-photography this is very important and cause problems, but might not solve all UV-cutoff needs for fluorescence-photography.

Edited by UlfW, 25 February 2019 - 06:46.

Ulf Wilhelmson
Curious and trying to see the invisible.

#39 cdhgamer

    Member

  • Members
  • 24 posts

Posted 25 February 2019 - 08:35

View PostCadmium, on 25 February 2019 - 04:06, said:

Once again, I didn't mean to say you need a filter on the lens, I was kind of saying the opposite.
Since you are using a stock camera, and a non-UV friendly lens, then you may not be getting much UV to your sensor.
I see a huge difference in UV between shooting the Convoy with the full spectrum D7000 + the Kuribayashi UV friendly lens, and the D610 or D810 stock cameras with modern kit lenses.
I just now tried all of this.

Camera Sensor < (Internal UV/IR-Cut filter) < Lens < (UV blocking filter) < < < < < U-340 (visual blocking filter) < Convoy S2+ 365nm Nichia LED

Shooting head-on at the U-340/Convoy, I see very weak UV with the D810 and D610 using modern Nikon lenses.
Using the Kuri lens instead, I see more UV with the D810 and D610.
Shooting with the D7000-UV/IR with Kuri, I see a LOT of UV.

So, the lens has a lot to do with how much UV is getting to the sensor.
When I put the Firecrest UV IR MC on the kit lens the UV becomes almost undetectable using my stock cameras.
I do believe the UV IR ME cuts more UV at a higher nm than does their UV 400 MC filter, regardless of the numbers, but I am not saying either of those filters should be used for cutting UV,
there are others, but I am not saying you absolutely need it either, given your stock visual equipment.
On the other hand if someone is using a full spectrum camera they pretty much need to cut the UV at 400nm to 435nm.
I am not familiar with the Tokina 100 mm Macro f/2.8, but it looks pretty modern, so it probably doesn't transmit UV well, of course, a lot of lenses will transmit some UV, down to 380...more? Don't know, they are all different.
If I were you, I would first try white balancing with NX-D, it is made for Nikon, and it would be rather handy to have, and it is free I think still. Try that first.

NX-D got me a tiny bit closer to what I saw but not quite all the way there. I did order a Firecrest UV 400 to try out though since it wasn't too costly, and I can always use it on my other camera when it comes back from a full spectrum conversion. I'll report back whether or not it helps in any way

#40 Cadmium

    Member

  • Members+G
  • 3,691 posts

Posted 25 February 2019 - 14:20

Here is a graph for the Firecrest UV IR MC below.
There are other alternatives for blocking UV. Just ask, and people will suggest what to use.

Frankly, Ulf's graph of the D810 internal cut filter that he linked to above seems to cut at about 420nm, for the most part, and that looks pretty good to me.
Regardless, it is good to have an external cut filter, but I don't know if very low amounts of UV leaking into your camera would keep your camera from seeing the fluorescing visual red you see.
Often you will find that green leaves will fluoresce red, and they can be used as a good red fluorescence test subject. You could find a leaf that fluoresces to your eyes, and test that with your camera,
if you can't get the camera to record a red fluorescing leaf, then I don't know...?

Attached Image: Firecrest_UVIR.jpg

Edited by Cadmium, 25 February 2019 - 14:51.