----- Original Message -----
From: "Don Roberts" <don.roberts@xxxxxxxxxxxxxxx>
To: "List for Photo/Imaging Educators - Professionals - Students"
<photoforum@xxxxxxxxxxxxxxxxxx>
Sent: Monday, May 05, 2014 8:10 PM
Subject: Re: sheen and iridiscence?
That was what I had asked, Karl. Is the loss of the iridescent effect due
to digital capture? Andy and I seem to have encountered the same problem
and believe it is. Film always captured it.
Don
On 5/5/14, 1:26 AM, karl shah-jenner wrote:
Don Roberts
"This bug was one of the most highly iridescent I have seen. That has
always shown up well on film before. This time digital did not capture
it. Is this characteristic of digital capture"
my answer - maybe, it depends on the bug
after all, some colours we see on insects (and birds feathers) are not
actually 'colours' but a perception of colour eminating from refraction,
interference or diffraction rather than pigment
see here for more info:
http://onlinelibrary.wiley.com/doi/10.1002/jmor.1052020106/abstract
me:
I have experience with diffraction causing colour renderings to go askew
in digital imaging where the sensors are more rigidly structured than
random grains in film, occasionally it can be overcome by changing the
distance at which the subject is photographed.
here's one tiny jumping spider I had issues with (digital) - the metalic
metallic iridescence rendered dull, the brilliant blue colour failed to
render at all
https://www.flickr.com/photos/smileyferret/149709068/
this mole cricket similarly came out dulled down, the water repelant sheen
was visible on film, not on digital
https://www.flickr.com/photos/smileyferret/149709653/sizes/o/in/photostream/
the photos were opportunistic, snapped when I encountered the things on
holiday - and this 2 inch wasp was busy hunting crickets underground when I
disturbed it so it was a tad angry with me when it emerged - hence the
blurry image - I got a number of images but this was the only one showing
the metallic colours reasonably well
https://www.flickr.com/photos/smileyferret/149709114/
again I could only conclude that digital sensors don't cope well with
refraction, interference or diffraction (one possible reason many cameras
advise against linear polarizers?) seeing the mole cricket rendered OK on
film and not on dgital, the wasp colours OK-ish when the wasp moved and
blurred but not when still, I would have to assume the sensors were the
issue
k
