• Ultraviolet Photography

LWIR, NIR & UV images from a solar plant

Infrared LWIR Multispectral
5 replies to this topic

#1 WiSi-Testpilot


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Posted 07 October 2018 - 21:24

On the 6th of October we took some pictures from a solar plant. The images are size reduced and enhanced. Unfortunately I have a bright spot in the middle of the NIR pictures. I found, that the SELP1650 is poor for NIR. Unexpected and very interesting are the patterns in the UV image. However, the patterns do not correlate with the defects. In the NIR and full-spectrum images, the patterns are not visible.

Full-Spectrum Sony A 6000, Lens SELP1650
IR Filter: Green.L, IR950,
UV Filter: Makario SP2 UV-400N

Thermal image: Flir Vue 336
Attached Image: 20181006_133143.jpg

Full_Spectrum_DSC01570: 1/800s, f/6.3, ISO-100
Attached Image: Full_Spectrum_DSC01570.jpg

NIR_DSC01520, 1/80s, f/6.3, ISO-1000
Attached Image: NIR_DSC01520.jpg

NIR_DSC01571, 1/60s, f/6.3, ISO-640,
Attached Image: NIR_DSC01571.jpg

UV_DSC01543, 1/3s, f/6.3, ISO-3200
Attached Image: UV_DSC01543.jpg

Best regards,

#2 Andy Perrin


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Posted 07 October 2018 - 22:18

The patterns in the UV image are probably because the solar arrays have a strong angular dependency that is enhanced in UV (where refractive indexes tend to be higher). It is probably interference effects in the layers of the solar cells.

Edited by Andy Perrin, 07 October 2018 - 22:20.

#3 BruceG


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Posted 10 October 2018 - 08:38

Interesting comparison, your IR image has a slight hot spot in the centre, I find that lens with more elements tend to have worse hot spot issue, my UV lens with simple optical design also works well for IR above 900nm.

#4 WiSi-Testpilot


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Posted 10 October 2018 - 11:56

Thank you for your replys. Today I took an image with a 760 nm Green.l filter (1/540s, f/4, ISO-100). It is almost without a hotspot. I will also order the Sony pancake lens SEL16F28, which contains only 5 elements. My current lens SELP1650 contains 9 elements. The pancake may be better above 900 nm and for UV too.
Best regards,

Attached Images

  • Attached Image: NIR_DSC01688.jpg

#5 Andrea B.

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Posted 10 October 2018 - 16:00

That is such an impressive solar array! Thanks for this interesting post.
We hope to have some solar panels eventually for our new house. So it is interesting for me to see how this might be done.

To add to Andy's comment, I was wondering if there might also be some condensation or humidity on the solar panels which might the mottled patterning in the UV photo.


Wilhelm, as Editor I took the liberty of pairing your captions with the photos. When you are making the post, place the cursor where you want the photo to appear within the text and then click the "Add to Post" button next to the uploaded photo icon. (This is not required, of course. I'm just explaining it in case it was not obvious.)
Andrea G. Blum
Often found hanging out with flowers & bees.

#6 WiSi-Testpilot


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Posted 13 October 2018 - 06:41

Andrea, thank you.
The solar plant belongs to a friend of mine. Our house is too small for a solar array and the roof has no orientation to the south, see image (Green.L, IR950, 1/60s, f/3.5, ISO-160).
Best regards,

Attached Images

  • Attached Image: NIR_DSC01605.jpg