In article ,
James Silverton not.jim.silverton.at.verizon.not wrote:

I haven't got the nerve (or ability, probably) to perform surgery on a
camera but how expensive a camera do you need for IR photography? I have
been impressed by the artistic quality of many IR photographs but not
their sharpness and those were taken with conventional film cameras.

I've successfully taken some interesting-looking IR photos using
inexpensive Nikon Coolpix cameras - specifically, the Coolpix 800 and
Coolpix 950. These use a 2.1-megapixel sensor (made by Sony I believe)
which has a less-than-efficient hot mirror... enough near-IR comes
through to allow IR photos to be taken in daylight with an exposure in
the 1/8- second range, as long as an IR-pass/visible-light-blocking
filter is added to the lens. I bought these cameras last year via
eBay auctions... around $25 for an 800 and around $45 for a 950, if I
recall properly.

I homebrewed a simple IR-pass filter as a "proof of concept", before
buying a good one. The simplest approach is to use several layers of
exposed photographic film. Another approach is to go to a plastic
store, and buy a scrap piece of black acrylic plastic sheet... this
stuff is made with a dye that passes a reasonable amount of IR. In
either case, the plastic or exposed photographic film can be mounted
to the front of a piece of opaque plastic tubing, which can then be
slid over the front of the camera lens assembly.

Better quality can be achieved with a purpose-made IR filter... the
Hoya RM-72 is the usual suspect. These filters pass more IR than the
simple homebrew type, I think.

Removing the hot filter from a camera of this sort, and replacing it
with clear glass would greatly increase the IR sensitivity and allow
for much shorter exposures (you'd still need an RM-72 or similar).
Removing the hot filter, and replacing it with a piece of IR-pass
filter glass would convert the camera to a high-sensitivity IR-only
camera... which is what several commercial camera shops can do for
you, for a significant fee.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
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