6 replies to this topic

[Andy Perrin]

Some kind of coneflower. Same setup as the Daisy fleabane, etc. with similar exposure times and processing.

Visible:


UVIVF:


UV:


1000nm long pass (Chinese filter alert, but I've roughly confirmed it using known bandpass filters stacked with it):


SWIR (1500-1600nm band pass):
(I had do to HDR on this in order to get both the dark center and the ray petals. The rays are really light, and the center is really dark, much more contrasty than shown.)


Center closeup without HDR:


Remarks:
Another example where the SWIR result does not really match any of the others. I am going to let this flower dry out and we will see what happens to the colors. Hopefully it's sturdy enough that it won't be unrecognizable. This flower followed the same pattern as the daisy fleabane (dark center, light ray petals) and they are obviously related to each other.

That UV is really REALLY dark. That flower would be invisible except for the specular reflections.

The 1000-1100nm IR looks nothing like the 1500-1600nm IR. I really want to get some more band pass filters and track the changes as you go more gradually to longer wavelength.

Edited by Andy Perrin, 12 July 2019 - 07:40.

[Cadmium]

Andy, I like that UVIVF shot.

[dabateman]

I know this question is off the flower, but I am interested in you backgound. Is that standard graph paper under the flower?
Interesting how I don't see lines in SWIR and Visible, but then dark in UV and bright in IR. It also seems to have Visible glow.
What is that.

[Andy Perrin]

Heehehee, in SWIR and visible, which I did first, I put white paper under the flower, so no lines. For UVIVF, I removed the paper because it fluorescences brightly, ruining the photo. I simply didn’t put the paper back under it for the remaining pics, so they have the lines also. As to what they are, it’s the base of my copy stand. The grid is a 1cm grid, so that should give some idea how big this flower is, incidentally.

Cadmium, thanks!

Edited by Andy Perrin, 13 July 2019 - 04:58.

[dabateman]

Andy,
Have you tried to do the whole range with just the triwave yet?
As in using most likely the Wollensak 25mm f1.5 lens, image in UV, visible, nir, swir?
I think that might be interesting, to eliminate any camera, lens differences in the spectral photos.

Also I find the UV photos will dramatically change depending on the light source. A monochrome flower like this using a 365nm led, will actually have a range of interesting yellow using a broad band UVb bulb, like an ExoTerra 200.

[Andy Perrin]

No, because I have no easy way to change filters. It takes 5-10 min or so per filter change, I would estimate. Each one has to be individually taped on. When I get my filter wheel going, I will probably try experiments like that.

[dabateman]

Andy,
I use one of these 25mm to 37mm step up rings:
https://www.ebay.com...=item1a211694c3

Then a 37mm to 52mm stepup for all my filters on the Wollensak.