Robert and all
My 2 bobs worth. Years ago I used to photographed calling frogs, with
macro lenses (100mm). I would first find the target calling frog on a
stream or pond with the uncovered torch light. When I found a calling
frog to photo I would move away and wrap several layers of red
cellophane over my torch to reduce the intensity of the light and then
very carefully and slowly get closer enough to the frog to fill the
frame. I usually shone the beam of the torch behind the frog and so had
only the edge of the beam so to speak lighting the frog. I focused by
moving the camera back and forward, not using the focus ring, and
focused on the eye shine. Many times I was successful in getting photos
and the dimmed red light and flash lights did not seem to bother the
frogs. They often call when a storm with lightning is about so I assumed
they are not blinded by flashing light. From experience I found that
trying to get close and photograph with a bright white light did not
work.
Greg Little
Greg Little - Principal Consultant
General Flora and Fauna
PO Box 526
Wallsend, NSW, 2287, Australia
Ph 02 49 556609
Fx 02 49 556671
www.gff.com.au
-----Original Message-----
From:
On Behalf Of Robert Inglis
Sent: Tuesday, 22 September 2009 11:05 AM
To: Birding-Aus
Subject: Re: Re: LED (by Mike Carter 21 Sept 2009)
Hi Mike,
Thanks for your comments on this topic. Unfortunately this is one of
those
topics in which many people are interested but almost none are prepared
to
contribute to the discussion. So, it was good to read your comments
which
provided some points that I had not considered or covered in my posting
on
this topic.
I agree with your comments on red filters. Red filters are really all
about
maintaining the observer's night vision and not about protecting the
viewed
creature's eyes. Such filters, depending on the density of the filter
element, will also reduce the intensity of the light beam and that is
probably why some night creatures (such as bandicoots) seem less
concerned
when such a light is trained on them, although, being mammals, their
night
vision is also less likely to be disrupted than if an unfiltered light
is
being used. However, the red filter may reduce the power of the light
beam
on low powered spotlights to the point where the light becomes
impractical
for spotlighting. I am not sure that spotlights with red filters are any
better, from a bird's point of view, than unfiltered lights but the
observer's night vision is less likely to be disrupted if spotlights
fitted
with red filters are being flashed about willy-nilly.
Perhaps the type of colour-tinted wrap-around glasses worn by some of
the
cricketers in night games would be a better proposition for participants
in
spotlighting activities but that would not help the creatures being
observed.
The point about identifying snakes at night by the light of a spotlight
with
a red filter is a good one. The same could be said about some bird
species
as well, I am sure, but other factors would make it easy to identify
birds
at night.
Incidentally, I would think that a discussion on identifying snakes has
as
much relevance on a birding forum as a discussion on mammals which is
basically what this discussion on spotlighting started as.
In that same vein, I understand that invertebrates can suffer eye damage
quite easily from strong light. I wonder if any of the "bug-botherers"
who
frequent BirdingAus have any comments they would wish to make publically
(or
privately) on that?
Maybe the frog-fanciers could comment on the effect of spotlighting on
frogs
eyes.
This document details some observations on using spotlights for
observing
possums:
http://www.wettropics.gov.au/res/downloads/info/possumsSpotlight.pdf
Mike, your comments re the "very little structured scrutiny of this
activity" are apt considering that there appear to be wildlife laws in
this
country concerning the use of spotlights on wild creatures.
And your comments about the economical and conservation benefits
involved in
the eco-tourism industry are important as well.
Cheers
Bob Inglis
Sandstone Point
Qld
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