Saturday, April 25, 2020

Reflected UV photography in polarized light IX - the Midas effect

Today more about UV polarizer experiments, using a special UV capable circular polarizer in front of my multispectral camera and UV-Nikkor 105mm lens, for recording some polarized reflected UV images. Object used were some leaves of a shrub. UV filter used was my classic Baader-U filter; Sunlight was used as light source. And a secret was used - but no, not a spraycan ;-)

[click on image gets you a larger image]

Here photographic results I got today. I called it the "Midas effect", I'm sure you'll notice why...

First Gold:

Then Silver:

Reflected UV photography in polarized light shows quite some usefulness, especially if there are (glossy) surfaces which change the polarization angle of light and which the polarizer filter makes visible. Downside is that one needs about 2 stops more exposure, due to the low approx. 25% transmission.

Some insects are able to see the polarization angle (and btw. we humans can also, but needs some traing: Haidinger's Brush) especially honeybees which navigate using the polarization angle of ultraviolet (UV) light.

I have written more about using UV polarizers HERE

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site