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UltravioletPhotography

Self-Portraiture in UV


eye4invisible

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eye4invisible

Hi all. Here's my first post to UVP: a selfie.

 

EXIF:

Nikon D3200 full spectrum | Nikkor 18-55mm kit lens @ 36mm | f/6.3 | 1sec | ISO 100 | Aperture Priority Auto | B+W 403 stacked with a Kolari Vision hot mirror filter.

 

Taken on a sunny February afternoon (before I got my Schott S8612, I used my hot mirror filter). Custom white balance set on grey concrete (without any filters attached). Auto-toning done in Photoshop, final levels tweaked in Lightroom.

post-116-0-38564600-1465011066.jpg

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Hi and welcome to our corner of cyberspace. It is nice to - literally - know the person behind the name... You do look like the outdoor kind of person?

 

I noticed you have run the camera at base ISO. This is understandable from an image quality perspective, however, the long exposure time does take away whatever gain in quality the low ISO acquired. Thus, using ISO 400 and even 800 should not be excluded. I use a 3200 myself for much of my UV work, as it has the Baader U built in for convenience. ISO 800 goes well enough if you process files with care.

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Or, you need to learn to hold more still when posing! (some 19th-century portraits had exposure times of minutes, yet they pulled it off somehow.)
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eye4invisible

I noticed you have run the camera at base ISO. This is understandable from an image quality perspective, however, the long exposure time does take away whatever gain in quality the low ISO acquired. Thus, using ISO 400 and even 800 should not be excluded.

 

Yes you're right, of course,and I just learned that recently (after this shot was taken). Even at ISO 100 there's some noise with my D3200, but through trial and error I've found that I can go up to ISO 400 (800 is too noisy).

 

Thanks for the advice! :)

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eye4invisible

What thickness is your S8612?

 

My S8612 is 3mm thick, however this one was taken with a stacked Kolari Vision hot mirror filter (thickness unknown). I suspect the IR cut on the KV filter is nowhere near as good as the S8612, although the KV filter seems to give better results for visible spectrum photography than the S8612.

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eye4invisible

There's always deconvolution... (This is with SmartDeblur 2.3.)

post-94-0-40860400-1465051457.jpg

Very interesting! Thanks for the pointer :)

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My S8612 is 3mm thick, however this one was taken with a stacked Kolari Vision hot mirror filter (thickness unknown). I suspect the IR cut on the KV filter is nowhere near as good as the S8612, although the KV filter seems to give better results for visible spectrum photography than the S8612.

 

Hi Andy, S8612 3mm for a UV stack would be extreme. Given UG1 (403) at 2mm-2.5mm the most S8612 you would need is 1.5mm, even 1mm should work, or 1.25mm. 3mm S8612 is roughly the same as using 6mm of BG40.

The drawback is that you are cutting the UV down a lot with the added thickness, not just the IR. I would say UG1 (403) 2mm + S8612 1.5mm would make a faster and well suppressed UV only stack.

 

Just for future reference, here is a comparison. I am guessing here at the 2.2mm thickness of the 403 (I think it is between 2mm and 2.5mm).

By the way, Hoya U-360 performs slightly better than UG1 in the same stacks.

post-87-0-56028800-1465114036.jpg

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eye4invisible

Hi Andy, S8612 3mm for a UV stack would be extreme. Given UG1 (403) at 2mm-2.5mm the most S8612 you would need is 1.5mm, even 1mm should work, or 1.25mm. 3mm S8612 is roughly the same as using 6mm of BG40.

The drawback is that you are cutting the UV down a lot with the added thickness, not just the IR.

 

Hi Cadmium, and thanks for the great info. So, in short, it looks like I made an expensive error in purchasing a 3mm thick filter.

 

I would say UG1 (403) 2mm + S8612 1.5mm would make a faster and well suppressed UV only stack.

 

Just for future reference, here is a comparison. I am guessing here at the 2.2mm thickness of the 403 (I think it is between 2mm and 2.5mm).

By the way, Hoya U-360 performs slightly better than UG1 in the same stacks.

 

The question I would have would be: if I was to purchase a Hoya U-360, could I use the S8612 3mm with it? Or would it be better to stick with the B+W 403 and get an S8612 1.5mm?

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So, in short, it looks like I made an expensive error in purchasing a 3mm thick filter.

 

Well, I would not say 'error'. The 3mm S8612 is useable, but it simply reduces the UV transmission from about 55% to 42% (approximately) as per Steve's charts. That just means a longer exposure time when shooting UV. So you can live with this filter for awhile, yes?? Later maybe sell it on Ebay eventually before it gets scratched up and replace it with something between 1.5 - 2.0mm.

 

*****

 

This reminds me that I need to gather up Charts and get links made over in our Filter Transmission Charts sticky.

I always have a looooong To Do list for our UV forum!!

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There's always deconvolution... (This is with SmartDeblur 2.3.)

 

I picked up the demo of that and played with it a bit. Interesting, but I found it hard to get much sharpening without creating a lot of artifacts. This might be wonderful for forensic use, but definitely limiting for artistic use. Or maybe I just don't have the knack somehow...

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Andy Perrin
OlDoinyo, it needs some practice and an image with very little noise to begin with. I have found that using my Neat Image denoising plug-in on it first substantially improves the results, especially if the image is relatively noise-free to begin with. Another thing is that one can edit the kernel by hand, which allows some improvement. And finally, since in reality the kernel varies throughout the image in most cases, I tend to use it to fix just the subject of the image, then I combine the sharpened image with the original, masking out everything but the subject. By doing that, I avoid introducing noise/artifacts into the background. All of that said, what you see above is probably about the best that can be done.
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eye4invisible

That just means a longer exposure time when shooting UV. So you can live with this filter for awhile, yes??

 

Yes, I can - I'm quite happy thus far. I may even just keep it as a spare hot mirror filter, just in case I ever damage or misplace my Kolari Vision HM.

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I am fairly sure that the vendor would happily exchange it for any other thickness in stock if you decided you wanted a different thickness. ;-)
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