Carduelis carduelis [European Goldfinch] Feather in UV, Visible and IR

[JMC]

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.)

 

[Cadmium]

Jonathan, Quite nice shot of the finches in flight!

Interesting also that a touch of yellow shows up in the UV.

[Andy Perrin]

I like the flying finches too. The UV is nifty.

[Andrea B.]

Now isn't that interesting that the light/dark signature is the same in all three wavebands? I wonder if that means anything?

[enricosavazzi]

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.

[Cadmium]

830/850nm is where it pretty much evens out. Anything above that is just for water darkness mostly.

[JMC]

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