# UV light



## davholla

How many people have tried this?  I have only taken one



IMG_7206ScorpionUVlight by davholla2002, on Flickr

I had one big problem it was very dark and I had to use slow shutter speed and f4 to take it.
I haven't tried again since, I keep forgetting but apparently all arachnids glow (most remember a tripod or something next time)
In case you are interested here it is under normal light



IMG_7201Scorpion by davholla2002, on Flickr

It was a Tityus (Atreus) forcipula adult male and I had picked it up for a second and later found that it can kill a person (hard to tell exactly how dangerous)


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## chuasam

Did you remember to remove your UV Filter?


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## davholla

chuasam said:


> Did you remember to remove your UV Filter?


I wanted the UV effect, so no I didn't.


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## 480sparky

davholla said:


> chuasam said:
> 
> 
> 
> Did you remember to remove your UV Filter?
> 
> 
> 
> I wanted the UV effect, so no I didn't.
Click to expand...


Um....... if you left your UV filter on, you didn't take a UV image.  You took an image with mostly 'visible' light.  Your UV filter (as well as the UV properties of the filter in front of your camera's sensor) prevented most of the UV light from reaching the sensor.

UV filters don't allow UV light to pass......... it blocks it.

To take a _truly_ UV image, you'll need to remove the UV filter built into the camera.  This is definitely *not* a DIY project.


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## davholla

Perhaps I was not clear, I was talking about taking photos under UV light - not UV photos.


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## Gary A.

I like it.  Interestingly, a newly molted Arachnid doesn't glow until the cuticle hardens.


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## davholla

Gary A. said:


> I like it.  Interestingly, a newly molted Arachnid doesn't glow until the cuticle hardens.


Have you tried it?    I must try some more shots - but time and other subjects have stopped me.


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## 480sparky

davholla said:


> Perhaps I was not clear, I was talking about taking photos under UV light - not UV photos.



The lamp that is producing the light may certainly be pumping out UV light, but you've filtered out  99.5% of it.  You've basically taken a visible light image, heavy on the blue end of the spectrum.

You can accomplish the same using an ordinary light source and a blue filter.


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## davholla

480sparky said:


> davholla said:
> 
> 
> 
> Perhaps I was not clear, I was talking about taking photos under UV light - not UV photos.
> 
> 
> 
> 
> The lamp that is producing the light may certainly be pumping out UV light, but you've filtered out  99.5% of it.  You've basically taken a visible light image, heavy on the blue end of the spectrum.
> 
> You can accomplish the same using an ordinary light source and a blue filter.
Click to expand...

How did I do that?  I didn't have a UV filter.


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## Gary A.

davholla said:


> Gary A. said:
> 
> 
> 
> I like it.  Interestingly, a newly molted Arachnid doesn't glow until the cuticle hardens.
> 
> 
> 
> Have you tried it?    I must try some more shots - but time and other subjects have stopped me.
Click to expand...

No, but I have seen it in the lab.  480sparky is correct.  What I have seen in the lab it a whitish-green glow (similar to Bioluminescent Algae), one needs to remove the camera's UV filter to capture the proper spectrum/color, in order for the captured image to reflect how our eyes would see it, (if we could see full spectrum UV).

Most standard digital cameras have a built in UV filter.


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## davholla

Gary A. said:


> davholla said:
> 
> 
> 
> 
> 
> Gary A. said:
> 
> 
> 
> I like it.  Interestingly, a newly molted Arachnid doesn't glow until the cuticle hardens.
> 
> 
> 
> Have you tried it?    I must try some more shots - but time and other subjects have stopped me.
> 
> Click to expand...
> 
> No, but I have seen it in the lab.  480sparky is correct.  What I have seen in the lab it a whitish-green glow (similar to Bioluminescent Algae), one needs to remove the camera's UV filter to capture the proper spectrum/color, in order for the captured image to reflect how our eyes would see it, (if we could see full spectrum UV).
> 
> Most standard digital cameras have a built in UV filter.
Click to expand...

Thanks that make senses, but if it is built in how can you remove it?


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## Alexr25

480sparky said:


> The lamp that is producing the light may certainly be pumping out UV light, but you've filtered out 99.5% of it. You've basically taken a visible light image, heavy on the blue end of the spectrum.


The whole point of the exercise would seem to be about capturing the florescence produced by the UV light rather than capturing the actual UV light so a UV filter would improve the effect.


480sparky said:


> You can accomplish the same using an ordinary light source and a blue filter.


No you can't! The scorpion won't fluoresce under ordinary light but even if it did the blue filter would probably block some of the fluorescing colors.


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## davholla

Alexr25 said:


> The whole point of the exercise would seem to be about capturing the florescence produced by the UV light rather than capturing the actual UV light so a UV filter would improve the effect.


That is correct, sorry if I was not clear, but if I have a built in UV filter why would another one help?


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## Alexr25

davholla said:


> That is correct, sorry if I was not clear, but if I have a built in UV filter why would another one help?


Probably adding another UV filter won't make any difference. Not only do you have a UV filter built into the camera sensor but modern lenses use UV cured cement  in their construction and that absorbs UV better than your average filter.


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## chuasam

Use UV sensitive film


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## petrochemist

The only Scorpions I have available are safely encased in plastic which unfortunately blocks most of the UV so they don't fluoresce. I've never tried it on other arachnids, might be worth a try as my 'Full spectrum' camera has very little UV response.

Fluorescence from man made materials can be fun to shoot as well


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## petrochemist

chuasam said:


> Use UV sensitive film


 I don't know of any film that's not UV sensitive. Film is very awkward to get the metering right for UV. Normal light meters whether in the camera or stand alone do not respond well to UV, and Lenses don't have UV focusing marks.
With film there's no ready feedback. Shooting a whole film with 1 stop bracketing should get your exposure right and possibly work out the focus shift....
If the UV light source isn't well controlled even well documented notes from a trial film may not be relevant on the next shooting. UV from daylight certainly varies hugely.


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## Designer

davholla said:


> ..if I have a built in UV filter why would another one help?


Who said install another one?  Nobody.  At least two people wrote that you should REMOVE ALL UV FILTERS if you're expecting to photograph UV light or the effects thereof.  

This modification is one that some photographers have ordered done to their camera for the express purpose of making UV photographs.  As far as I know, that procedure is non-reversable, so you should think very carefully about having it done.


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## BananaRepublic

480sparky said:


> davholla said:
> 
> 
> 
> 
> 
> chuasam said:
> 
> 
> 
> Did you remember to remove your UV Filter?
> 
> 
> 
> I wanted the UV effect, so no I didn't.
> 
> Click to expand...
> 
> 
> Um....... if you left your UV filter on, you didn't take a UV image.  You took an image with mostly 'visible' light.  Your UV filter (as well as the UV properties of the filter in front of your camera's sensor) prevented most of the UV light from reaching the sensor.
> 
> UV filters don't allow UV light to pass......... it blocks it.
> 
> To take a _truly_ UV image, you'll need to remove the UV filter built into the camera.  This is definitely *not* a DIY project.
Click to expand...


Thats a double burn


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## davholla

Designer said:


> davholla said:
> 
> 
> 
> ..if I have a built in UV filter why would another one help?
> 
> 
> 
> Who said install another one? .
Click to expand...

I thought that post 12 had done so.


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## 480sparky

davholla said:


> chuasam said:
> 
> 
> 
> Did you remember to remove your UV Filter?
> 
> 
> 
> I wanted the UV effect, so no I didn't.
Click to expand...




davholla said:


> How did I do that?  I didn't have a UV filter.



So........... did you, or did you not, remove a UV filter?





davholla said:


> Thanks that make senses, but if it is built in how can you remove it?



You send it to a specialist like These People who will be more than happy to do it for you.





chuasam said:


> Use UV sensitive film



Err...... I'd like to see you load it into a DSLR..........


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## Designer

davholla said:


> I thought that post 12 had done so.





Alexr25 said:


> The whole point of the exercise would seem to be about capturing the florescence produced by the UV light rather than capturing the actual UV light so a UV filter would improve the effect.


I'm unsure if this is accurate, so maybe a test is in order.  

It does seem to me however that you would have to use the same light that created the fluorescence in the first place, which is UV, regardless whether the UV light was directly entering the lens or if it was simply being reflected by your subject.  

Go ahead and run a quick test of Alexr25's hypothesis and report back.


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## Alexr25

Designer said:


> REMOVE ALL UV FILTERS if you're expecting to photograph UV light or the effects thereof.


Your eyes don't respond to UV but can still see the fluorescence produced by UV light in many materials so how is a camera any different? Blocking UV from the sensor will prevent the "effects", fluorescence, from being swamped by the actual UV light. In any case even without any UV filters present most modern camera lenses do a good job of blocking UV light.


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## davholla

480sparky said:


> davholla said:
> 
> 
> 
> 
> 
> chuasam said:
> 
> 
> 
> Did you remember to remove your UV Filter?
> 
> 
> 
> I wanted the UV effect, so no I didn't.
> 
> Click to expand...
> 
> 
> 
> 
> davholla said:
> 
> 
> 
> How did I do that?  I didn't have a UV filter.
> 
> Click to expand...
> 
> 
> So........... did you, or did you not, remove a UV filter?
> 
> 
> 
> 
> 
> davholla said:
> 
> 
> 
> Thanks that make senses, but if it is built in how can you remove it?
> 
> Click to expand...
> 
> 
> You send it to a specialist like These People who will be more than happy to do it for you.
> 
> 
> 
> 
> 
> chuasam said:
> 
> 
> 
> Use UV sensitive film
> 
> Click to expand...
> 
> 
> Err...... I'd like to see you load it into a DSLR..........
Click to expand...

No I didn't and perhaps I was not clear, I talking about the fluoresence created not UV light.  I hope this is clear now.


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## Designer

davholla said:


> No I didn't and perhaps I was not clear, I talking about the fluoresence created not UV light.  I hope this is clear now.


I think I understand it.  What did you think of the website that was linked?  Are the examples they have helpful?


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## petrochemist

Designer said:


> davholla said:
> 
> 
> 
> I thought that post 12 had done so.
> 
> 
> 
> 
> 
> 
> Alexr25 said:
> 
> 
> 
> The whole point of the exercise would seem to be about capturing the florescence produced by the UV light rather than capturing the actual UV light so a UV filter would improve the effect.
> 
> Click to expand...
> 
> I'm unsure if this is accurate, so maybe a test is in order.
> 
> It does seem to me however that you would have to use the same light that created the fluorescence in the first place, which is UV, regardless whether the UV light was directly entering the lens or if it was simply being reflected by your subject.
> 
> Go ahead and run a quick test of Alexr25's hypothesis and report back.
Click to expand...


I have several older books with sections on UV fluorescence photography. Most of them INSIST that a UV filter is fitted.
I suspect most are from film days as film is far more sensitive to UV than digital, but if you have a UV filter it certainly won't do any harm to fit it. In everyday photography without a powerful UV source available I certainly wouldn't bother with a UV filter but that's a different story!

I suggest you read up a little on fluorescence.
Fluorescence is a chemical process where an energetic form of radiation is used to excite a material, which then relaxes after a very short delay (no more than a few milliseconds).
This relaxation is usually via multiple transitions all of lower energy than the excitation. Lower energy means longer wavelengths.
There are some rare cases of fluorescence that emit at the same wavelength as their excitation. To view these a very rapidly pulsed light is needed, with the fluorescence only visible immediately after the light source has gone off.


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