Re: Infrared photography?

"raydunakin@xxxxxxx" <raydunakin@xxxxxxx> wrote in
news:1128041337.525508.5720@xxxxxxxxxxxxxxxxxxxxxxxxxxxx:

> Will infrared film work in an ordinary 35mm camera?

In most cases, yes. It needs to be loaded in total darkness, though.
Several of the newer camera bodies, such as most Canon EOS, use an infrared
sprocket counter to frame and advance the film, and this will fog the edges
of the frames.


> Is it color, or
> black and white?

The commoner types are B&W, but there is color IR available, and it
will specify this on the package (and cost a lot more). There are various
sensitivities, but most B&W IR films are fairly close to the same response.


> Does it require any special filter or other treatment?

Typically, yes, to get the best effect. IR films are still sensitive
to visible light, so to achieve the most radical results, you would use a
filter that blocks most of the visible light, such as an R72 or #87 or #89.
This generally means some pretty long shutter speeds, though, even in
extremely bright conditions.


> What about processing -- can it be processed at any 1-hour lab, or does
> it need special processing?

Most B&W IR films can be processed in standard B&W chemicals, though
a lab that isn't used to it may not know what development times to use. B&W
is easy enough for you to process yourself, though, and any lab that
handles B&W can do prints from the negatives.

As for the color, you may have an option for processing - Kodak's can
be processed standard E-6 (slide) chemicals for false colors, or AR-5 for
accuracy. Though this is an amusing concept for IR... ;-)

Several things to bear in mind: IR wavelengths reflect quite
differently than visible light, usually quite brightly from foliage and
poorly from water, as well as getting minimal response from the sky. The
brighter the sunlight, the stronger the overall response - in cloudy
conditions the IR effect is reduced way too far. But basically, you'll get
bright white leaves on the trees against a nearly black sky. The only
example of mine online is at http://www.pbase.com/shootin/image/43718608,
since I just mess around with it.

The film is sensitive to heat and 'decays' rapidly, so storing it at
room temperature means it'll die out in a month or less, faster if the temp
is higher. It's also reasonably slow, and this isn't helped with the
filters, so a breezy day will produce blurs from the foliage, and you
definitely want a tripod.

Camera lenses are optimized for the visible spectrum, and IR is off
the end of that, so it will actually be out-of-focus at the same lens
settings when compared to the visible scene. There are tricks to get around
this, usually shooting at small apertures for high depth-of-field, but
refocusing helps a lot, and some lenses have IR marks on them to allow you
to focus accurately. Other people get their focus visually and then add an
extension tube to the lens.

A lot of digital cameras actually have a fair range of IR sensitivity
from the sensors, and this can be exploited in various ways. Sony's F717
and F828 are already set up to use IR, so the addition of a filter works
well. Canon's Pro 90 isn't intended for this, but it does it anyway. Others
have an IR filter internally that you may have to disable. It's fairly easy
to check the sensitivity, too - simply aim a TV remote at the camera and
hold any button while watching the image in the LCD. If you get a
flickering light (don't expect it to be red - mine comes up light blue),
then you should be able to produce results with an IR filter. The benefit
of this is that the camera will probably autofocus correctly with the
filter and require no shenanigans with getting tight focus.

Do a websearch on IR photography to find out plenty of details. The
most expensive parts are the filters.

Have fun, and good luck!


- Al.

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