• Ultraviolet Photography

Shrubby Cinquefoil (vis, UV-A, SWIR 1500-1600nm)

Multispectral SWIR Infrared
2 replies to this topic

#1 Andy Perrin


  • Members+G
  • 4,425 posts
  • Location: United States

Posted 04 September 2019 - 17:39

This is a cultivar, found growing in a bush. It matches the existing UV signature for that species on the site here. (The only other thing it could be is dwarf cinquefoil, but the leaves don't match. Or, I suppose, some other cinquefoil that we don't have a record of on the site yet.)

Of note, the SWIR image showed some interesting effects on the anthers(?) around the center of the flower. (I am not confident of my botanical vocabulary here.)

Visible and UV-A photos were taken with the Resolve 60mm lens on my old NEX-7 camera (which is APS-C and therefore is better covered by the small image circle of the Resolve lens). SWIR was with the TriWave camera. I did not record exposure info.

Visible (BG38 2mm+DB850 stack)
Attached Image: _DSC9638 vis UVP.jpg

UV (330WB80 filter)
This image is an HDR made from 4 exposures, because those petals were very very dark.
Attached Image: _DSC9640 UV UVP.jpg

SWIR (Thorlabs 1500nm long pass filter, and the camera cuts off at 1600nm)
This is a pano (as all my SWIR pics are now, since that's the only way to get a decent resolution). I also oversharpened it, but oh well.
Attached Image: shrubby cinquefoil SWIR UVP.jpg

Edited by Andy Perrin, 04 September 2019 - 17:53.

#2 dabateman

    Da Bateman

  • Members+G
  • 3,007 posts
  • Location: Maryland

Posted 05 September 2019 - 01:51

I like the SWIR the most. The damage on the petals is most visible as well as the accent of the antlers.
Very cool.
What is the resolution of triwave image?

#3 Andy Perrin


  • Members+G
  • 4,425 posts
  • Location: United States

Posted 05 September 2019 - 02:29


What is the resolution of triwave image?
Good question. Each single image is 640x480, but reading closely in the handmade manual, I came across a comment that some models put one microlens for each group of 2x2 pixels, thereby changing it to 320x240 but with more photons per group of pixels. This image was made from 50 images that overlap considerably, leading to a final image of 1429x987. This was then reduced and (unfortunately) oversharpened and I saved over the original by accident!