I assume that this won't work with DSLRs that have an IR filter over
the sensor. Is that correct?
Roger
On 12 Feb 2008, at 5:11 PM, ADavidhazy wrote:
Hi,
This may have been already reported elsewhere but as one who
several years ago
mentioned that reversal film processed to maximum density (not
exposed but
developed) could be used as a makeshift infrared passing, light
blocking, filter
I though I'd pass this tidbit along for those who have not thought
of this
other reasonably priced alternative.
Assumption is that many photographers are getting rid of their
colored filters
since they can do adjustments in Photoshop or similar. HA!
So, this means that prices of glass photographic filters must be
dropping. I
suppose that many "junk" piles in photo stores have such discarded
filters in
the $.50 bin. Glass filters are generally of much better optical
quality than
photographic film even if stacked!
So, if you couple a blue filter with a red filter you will probably
notice that
the combination is pretty opaque. In fact, it may be so opaque that
unless you
are looking directly at the filament of a tungsten lamp you will
not see through
the combo. And if you perceive something it might have a deep
reddish tinge. This
is common to filters such as the Wratten 87.
Anyway, if you'd like to make true infrared photographs but are
lacking a true
infrared transmitting filer try scrounging up a red #25 and a blue
$47B filter
or similar and stacking them photograph through the combination. It
may just
be what you needed.
I tried this with a Fuji FinePix S9100 IR (infrared modified camera
designed
for quickie use in forensic applications) and the improvisation
worked perfectly.
BTW, I got the camera through a local student organized auction to
which Fuji
donated the camera. Fixed lens DSLR with live preview, etc. Neat
little package!
cheers, Andy Davidhazy
