JMC Posted August 9, 2019 Share Posted August 9, 2019 Crowther, J.M. (2019) Feather of Carduelis carduelis Linnaeus (Fringillidae) European Goldfinch. Feather photographed in visible, infrared and ultraviolet light. LINK Location: England Comment: We get Goldfinches in the garden here. For those that don't know these lovely little birds, they are very colourful and are always chattering. Below is an image I took last year - 3 of them at the feeder. While in the garden a couple of days ago I found a small feather from one. So I did UV, visible and IR images of it. Gear: Canon EOS 5DSR multispectral, Rayfact 105mm UV lens, single Bowens GM500 flash head with un-coated glass bulb at about 45 degrees to the camera. Filters: UV - Baader U Visible - BG39, 2.5mm (Chinese) IR - Heliopan 715nm Camera and lens settings vary between the UV, Vis and IR. Images were captured as RAW and then white-balanced from PTFE disc imaged with the different filters. Resized and cropped for here, but not further modified for brightness or contrast. Visible UV Wasn't sure what to expect with the UV image, but there is still a hint of the yellow there. IR Can't really see any yellow colour with the IR one. (See later post in this topic for more IR images of the feather.) Link to comment
Cadmium Posted August 9, 2019 Share Posted August 9, 2019 Jonathan, Quite nice shot of the finches in flight!Interesting also that a touch of yellow shows up in the UV. Link to comment
Andy Perrin Posted August 10, 2019 Share Posted August 10, 2019 I like the flying finches too. The UV is nifty. Link to comment
Andrea B. Posted August 10, 2019 Share Posted August 10, 2019 Now isn't that interesting that the light/dark signature is the same in all three wavebands? I wonder if that means anything? Link to comment
enricosavazzi Posted August 10, 2019 Share Posted August 10, 2019 A 715 nm cutoff of the NIR-pass filter is still quite close to VIS, so it is expected that some of the VIS pattern still shows. At 900 or 1,000 nm probably there is little or no trace of the VIS pattern. Link to comment
Cadmium Posted August 10, 2019 Share Posted August 10, 2019 830/850nm is where it pretty much evens out. Anything above that is just for water darkness mostly. Link to comment
JMC Posted August 10, 2019 Author Share Posted August 10, 2019 Thanks all. The image with 3 Goldfinches was a bit of luck to get them all in focus at the same time. I've taken some more images with some more IR filters. Heliopan 780 Heliopan 830 Heliopan 1000 Link to comment
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