IR Filters

Started Mar 12, 2003 | Discussions thread
Mario Carlo
Regular MemberPosts: 361
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Re: take a look at ....
In reply to John Glover, Mar 13, 2003

John Glover wrote:

You might check out http://www.cliffshade.com/dpfwiw/ir.htm .... I
have found the S602 to work fairly well with the Hoya 72R.

My 6900 also works well with the Wratten 87 series of gel filters.
Just use a Cokin holder system with the gel filter adapter and they
easily mount on the adpater tube. However, the 87 series filters
completely block visible light, so your intial exposures are
guesses.......

As far as Mario's question about day or night use goes, these are
filters, they are not detectors. As such, the IR filter is
filtering out the bulk of the shorter wavelength visible light and
only allowing through IR light reflected off your subject.
Therefore, they are really only effective during the day when
reflected IR light is strong. I suppose if there was an intense
enough point source at night, you'd also get a reflected IR image.

But you are not going to get what many people think of as an IR
image at night. That is thermal imagery, which measures IR
radaition generated by a source. Thermal Ir imagery, such as that
used FLIR cameras, uses an entirely different (and very
expensive) detector systems to detect and ampliy thermally emitted
IR radiation........a completely different concept than what the
basic IR filter we've been discussing will do.

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John

Fuji 6900Z, Fuji2600Z,
Pentax PZ-1p, Pentax ZX-M, Pentax MX, Oly Stylus
http://www.pbase.com/jglover

-- hide signature --

Thanks John. This has been alot of help.

I'll give the Hoya 72R try. Seems like the choice for me. I tried some PS plugins and actions and they just don't seem to cut it.

MArio Carlo
http://www.pbase.com/mariomel

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