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UltravioletPhotography

Seeing how my Tamron 1:1 Macro does with UV


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KarlBlessing

More than half the lenses I use for my M-4/3 cameras are manual focus lenses, mostly older vintages (around 1950s-1970s, with a few from the 80s), one of my lucky aquisitions back when I worked for a camera shop over 15 years ago was this Tamron SP Adaptall-II 90mm f/2.8 1:1 macro lens (model 72B I think, the little sticker got lost years ago), using an Adaptall-to-MFT adapter.

 

Like my Panasonic 42.5mm f/1.8 O.I.S. and My Panasonic 20mm f/1.7, it seems to pass UV light pretty well from my old Photogenic Powerlight 750W (which I didn't expect to be a visible source because it required a full power discharge and rather high ISO to my little Pentax Q10).

 

This is a dead little succulent plant, no clue why we kept it on the table, but it's a decent texture to try to capture and shows up quite vividly on the infrared side.

 

The exposure on this for UV (using a LUV U II by uviroptics, 320~395nm, 360nm peak) , 1/200th f/11 ISO 800, strobe was a little over 1/4 power from about 2 feet away.

 

HvYHqLB.jpg

 

Same setting, different kind of subject (a pencil sharpener for my 5.6mm clutch pencil, and a vintage gold dip pen with a broken ivory tail, white balance/etc tweaked so that it almost seems normalish, but is still thru the LUVUII filter.

 

yabgma5.jpg

 

And then the same little dead plant but in 1,000nm+ Infrared (Schott RG1000), exposure being reduced to 1/16th power, raised about 4 feet away, ISO dropped to 200, but same aperture. Would have been much more sensitive if I slapped on my RG850, my strobe seems to push out a lot more IR than it does visible or UV light.

 

NAJhxMY.jpg

 

Though it does make me wonder about the years of using models in front of the Photogenic Powerlight 750... all those flashes that clearly contain UVA light, right into their eyes... been using these strobes since at least 2006.

 

qmn075h.jpg

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Andy Perrin

Both UV images look very odd for UV. I wonder if the vast amount of IR is punching through the filter a little. Even well blocked filters will leak if the IR:UV ratio is tilted too far to the former. Especially if the lens doesn't have good bandpass...

 

Maybe try stacking it with a long pass at same exposure setting and distance to see if anything is getting through?

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KarlBlessing

In comparison, these two are done with the Panasonic 42.5 f/1.7 O.I.S. , autofocused. Frontal view is 1/200, f/2.0, ISO 200 at about 1/16th strobe power. Top view is f/2.8 ISO 400.

 

mx1xapD.jpg

 

XEtQ2rm.jpg

 

I included a prescription bottle because I know the transparent amber plastic is designed to block UV light, and shows up opaque here.

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Andy Perrin
All the colors still look really odd for UV. I don't know if it's narrow bandpass (so, all UV but maybe not very far in) or contamination with some other light, or maybe just peculiar white balance? But if you look around on the forum, nobody else has this palette.
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KarlBlessing

Both UV images look very odd for UV. I wonder if the vast amount of IR is punching through the filter a little. Even well blocked filters will leak if the IR:UV ratio is tilted too far to the former. Especially if the lens doesn't have good bandpass...

 

Maybe try stacking it with a long pass at same exposure setting and distance to see if anything is getting through?

 

The Luv U II is stated as "This filter transmits UV in the range of 315nm to 395nm, with a 360nm center peak transmission, suppressing visual and IR to 1E-04 or below.", a SCHOTT UG11 UV Bandpass filter stacked with S8612 glass (Vis/IR suppression), so it already has the IR suppression on it.

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KarlBlessing

All the colors still look really odd for UV. I don't know if it's narrow bandpass (so, all UV but maybe not very far in) or contamination with some other light, or maybe just peculiar white balance? But if you look around on the forum, nobody else has this palette.

 

It's not straight out of the camera, there's some pulling and hue adjustments with the very narrow amount of either flare or false color done in adobe camera raw before getting into photoshop.

 

9OfMBxw.png

 

The Jpeg would be the straight out of the camera interpretation of it, white balanced to the paper.

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Andy Perrin

The Luv U II is stated as "This filter transmits UV in the range of 315nm to 395nm, with a 360nm center peak transmission, suppressing visual and IR to 1E-04 or below.", a SCHOTT UG11 UV Bandpass filter stacked with S8612 glass (Vis/IR suppression), so it already has the IR suppression on it.

Yes, and I'm telling you that it's possible to punch through almost any suppression if you tilt the IR:UV ratio far enough. Don't imagine that any filter is bulletproof. They all leak if you push enough out of spectrum light through.

 

It's not straight out of the camera, there's some pulling and hue adjustments with the very narrow amount of either flare or false color done in adobe camera raw before getting into photoshop.

HMMM. Okay, so Adobe Camera Raw is known for NOT being able to set a proper UV white balance, which might explain everything. We mostly use PhotoNinja or DarkTable or a few others.

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KarlBlessing

Yes, and I'm telling you that it's possible to punch through almost any suppression if you tilt the IR:UV ratio far enough. Don't imagine that any filter is bulletproof. They all leak if you push enough out of spectrum light through.

 

It's possible considering how much stronger the IR output is to the other bands from the strobe. I would likely have to filter at the light source to get pure UV illumination, but also possible that I pushed the hell out of it in post if you see how it came out of the camera above.

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KarlBlessing

HMMM. Okay, so Adobe Camera Raw is known for NOT being able to set a proper UV white balance, which might explain everything. We mostly use PhotoNinja or DarkTable or a few others.

 

Is there such a thing as "proper UV WB" ? Other than just making it monochromatic.

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Andy Perrin

Is there such a thing as "proper UV WB" ? Other than just making it monochromatic.

Well, on this forum we have defined a STANDARD UV white balance, anyway, so I guess you can quibble with the word "proper" but there is one that naturally appears if you white balance off PTFE using any of the programs that we know work for UV white balancing.

 

Here is the Sticky for white balance in UV. Please read.

https://www.ultravio...ir-photography/

 

Anyway, long story short, you can use any colors you want for artistic reasons but it makes it hard to interpret the images if they aren't white balanced in the way described above.

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KarlBlessing

Well, on this forum we have defined a STANDARD UV white balance, anyway, so I guess you can quibble with the word "proper" but there is one that naturally appears if you white balance off PTFE using any of the programs that we know work for UV white balancing.

 

Here is the Sticky for white balance in UV. Please read.

https://www.ultravio...ir-photography/

 

Understood, and checking out those materials.

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KarlBlessing

Well, on this forum we have defined a STANDARD UV white balance, anyway, so I guess you can quibble with the word "proper" but there is one that naturally appears if you white balance off PTFE using any of the programs that we know work for UV white balancing.

 

Here is the Sticky for white balance in UV. Please read.

https://www.ultravio...ir-photography/

 

Anyway, long story short, you can use any colors you want for artistic reasons but it makes it hard to interpret the images if they aren't white balanced in the way described above.

 

Initial result from Photo Ninja, though I need to pick up some of the balancing materials you linked to. This is from the Panasonic 42.5 f/1.7 btw.

 

mnFmUTN.png

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Andy Perrin
Yup, that looks like what I would expect to see. It was definitely ACR then that was causing the colors to look different.
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If you have plumbing tape or that thin white stuff you use to lubricate a pipe when screwing on a shower head in your bathroom. Than you have some PTFE. Just wrap 3 to 4 layers around an old business card and your good to go.

If that gets tiresome, then you can buy a cheap block of virgin white PTFE from Ebay.

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Dave I am having more luck with difficult CWB by using a thin, <0.2mm, PTFE in a filter holder / ring & shooting the CWB through it.
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KarlBlessing

Dave I am having more luck with difficult CWB by using a thin, <0.2mm, PTFE in a filter holder / ring & shooting the CWB through it.

 

Like creating an expodisc for UV purpose.

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KarlBlessing

Yes, but it works for UVA, Visible & IR light too.

 

Noticing that earlier today when I did the plumber tape suggestion, particularly decent when shooting unfiltered.

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Noticing that earlier today when I did the plumber tape suggestion, particularly decent when shooting unfiltered.

 

Good

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If you don't want to bother with PTFE there are some other common surfaces which reflect UV fairly evenly across the spectrum--but paper is not one of them. It tends to contain whiteners which reflect long-wave UV much more than short-wave UV.
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