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UltravioletPhotography

Trying For Some Black Water


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Trying to get some 'Black Water' with my converted Sigma fp. I wonder if it will see 'Black Water' with a 1200nm ?

 

First with a 950nm filter.

 

Second with a 1000nm filter.

 

post-31-0-66307000-1620618782.jpg

 

post-31-0-98964600-1620618813.jpg

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The second peak is at 1205nm but the camera sensor is dead there. Best peak is 976 with a narrowband filter.

 

I wasn't sure what the peak was, so I am either side of the peak.

I can't check with my spectroscope as it only goes to 850nm but these two filters don't leak down to 850nm thank goodness.

Do you reckon the water would be darker then this at 976nm ?

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Andy Perrin

Yes, but the peak isn’t that big so only a little. To get really ink black water you need to be in SWIR at 1450nm.

 

You can also exaggerate the effect by using deeper water. Try a bathtub.

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Looks nice. As Andy suggested, you would get better results with that narrow bandpass filter, but the effect is already visible.
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Looks good.

Lighting source will matter too. An Led is bad as very little in that wavelength. Look outside or with a halogen bulbs. I think it was a Halogen bulb that was better than an incandescent bulb when I was trying this.

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White LEDs have some far red up to 750 nm, maybe some more but after 800 nm there's nothing. If you want to use LEDs they are available at 970-980 nm, I have one but I didn't use it yet at full power since it requires a heatsink.
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Andy Perrin
Sounds fine. If you could see significant amounts of red light with your eyes then probably there was plenty of near infrared also.
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