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Digital Imaging Beyond the Visible
Shooting Infrared Photographs with Your Digital Camera
by Chris Maher and Larry Berman
Featured in the February 2002 issue of Shutterbug
Magazine
*Chris got the Shutterbug cover*
This article is expanded to include example images on our companion web site:
www.InfraredDreams.com
Including a mini review of the the Sony DSC-F707
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Shooting Infrared with the CoolPix 5000
Sony DSC-F707 Infrared Gallery |
Mouse over this image to see it in infrared |
Years ago I used to love to shoot Kodak High Speed
Infrared Film. You never knew exactly what you would get until after it
was processed. But, oh what amazing images could be made! Green foliage
glowed white, people’s skin could change to an ethereal complexion, and
sunny skies could range from jet black to a rich silvery gray. But exposure and composition was all guesswork. How much IR was in any
given scene? Your camera’s light meter didn’t know. Even focus was a
guess, as IR wavelengths focus at a different point than visible light.
And the really effective filters blocked all visible light – a severe
handicap for SLR cameras.
All that has changed with the advent of digital cameras. Most have CCDs
that are sensitive to the part of the spectrum known as “near infrared”.
Put the right filter in front of the lens to block visible light, and the
camera will automatically adjust its focus and exposure, showing you the
resulting infrared image on your cameras LCD in real time. For those who
have worked with infrared films in the past this is nothing short of a
miracle.
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What is Infrared Light
and Why Do Plants Seem to Glow with it? |
Technically, the part of the spectrum that most digital
cameras can see is called near infrared. It is composed of the frequencies
just below visible red light, starting at a wavelength of around 700 nm
(nanometers). These longer wavelengths often are absorbed or reflected
quite differently than visible light. Most noticeable is the way that the
internal structure of leaves strongly refracts near IR. The resulting
brightness is dependant on the type of leaf and it’s health. Other things,
such as still water or a deep blue sky will absorb IR, and thus appear
very dark. |
Can My Camera Do This? |
Most CCDs are sensitive to more than the visible light
spectrum. Manufactures often compensate for this by including a “hot
mirror” to block infrared light, and thus maintain a true color balance.
The simple way to tell if your camera is going to see IR is to take a TV
or VCR infrared remote control and point it at your camera. Push a button
on it and look on the LCD for a spot of light. You should be able to see a
point of light. If you do, you will be able to shoot IR images with your
camera.
Next, you will need to buy a filter that will block all visible light,
but allow infrared radiation to pass. Different filters block varying
amounts of shorter wavelength light. In increasing degree of strength are
the Wratten #89B, Wratten #88A, Wratten #87, and Wratten #87C filters. I
have had great results with an inexpensive 88A filter from Harrison and
Harrison (1835 Thunderbolt Drive Unit E, Porterville, CA 93257-9300 phone
559-782-0121)
If your camera has no thread for a screw in filter, you can buy gelatin
filters and cut them down to fit over your lens, and tape them in place. I
find gelatin filters especially helpful for supplemental lenses like
Nikon’s fisheye. I just cut a small circle the size of the rear element of
the lens, and place it between the camera and fisheye before I screw it in
place.
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Shooting Technique |
When you place a sharp cut IR filter in front of your
digital camera's lens, you are granted entry to an invisible world.
Surreal landscapes unfold with unexpected graphic elements, such as inky
black skies or open luminous shadow areas.
To compose really strong images in this netherworld requires close
examination of your cameras LCD. This presents a problem since LCD screens
are very hard to see in bright outdoor light. One solution is to use a LCD
screen hood and magnifier like the
Xtend-a-View™.
This clever device fits over your camera’s LCD, blocking all extraneous
light, and magnifies your screen by a factor of 2x. Or just use a camera
with an electronic viewfinder, like the Canon Pro90 IS.
When I go looking for infrared images, I'll often walk with one eye to
the LCD viewfinder and the other open to see what's around me. I shoot
lots of images, as there are no expensive film and processing costs to
deal with.
Depending on your cameras sensitivity, exposures can be fairly long,
even in direct sun. The Nikon CoolPix 990 may need up to a 15 second
exposure. I usually shoot at around 1/15 of a second with the more
sensitive CoolPix 950, and 1/8 of a second with the Canon Pro90 IS. If
your camera allows you to increase the apparent ISO, that will help a bit.
Features such as the CoolPix “Best Shot Selector” or the internal Image
Stabilizer in the Canon Pro 90 IS really help with long exposures. Each is
so effective that I find I rarely need a tripod.
A tripod can be very useful, however, as it will allow you capture
intriguing pairs of color and infrared images. Just shoot with the filter,
then remove it and take a second shot. The two images will be in perfect
register, and will allow you to experiment with mixing colors with your
infrared image using a program like Photoshop or Paint Shop Pro.
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Choosing your Subjects |
Plants are quite spectacular in the way they glow.
Healthy leaves can go almost white, while dead and dying vegetation is
often quite a bit darker. The bark of trees can range from a rich black to
a birch like white.
People’s skin can glow with a soft light, and occasionally a
latticework of small veins can be seen just beneath the surface. Eyes can
be quite spooky, as the iris can absorb or transmit infrared in unexpected
ways.
Bodies of water can reflect IR if the surface is in motion, but will
tend to absorb it if it is still. Shallow water is often quite
transparent.
The sky will range from a light gray to black, depending on the angle
you are shooting relative to the sun, and the kind of atmospheric
particles causing backscatter. Clouds are often brilliant white, becoming
strong visual elements.
Cityscapes can be richly varied, as buildings reflect and absorb
different amounts of IR, and overall image clarity is often dramatic, as
atmospheric scattering of near IR wavelengths is generally quite low.
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Post Processing the Image |
Your infrared images may have some strange color and
tonal balance to them right out of the camera. Some may go quite red;
others may have a cyan sheen. Rarely will they have a full tonal range.
Adjusting curves and levels in a program like Photoshop will allow you
to clean up the image. I like to convert my RGB images into true grayscale
before I print them. Sometimes I’ll simply desaturate the image, other
times I find there is less noise in the image if I converted to LAB mode
first, choose the lightness channel, and then convert to grayscale.
Photoshop also provides the means to produce other classic infrared
film effects. Kodak High Speed Infrared Film was quite grainy, and had no
anti-halation backing. This caused the highlights to flare and glow with a
soft, dreamlike effect. You can add both these effects to your digital
images using Photoshop’s Diffuse Glow filter.
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Printing Your Images |
Inkjet printers can do a marvelous job of creating black
and white prints. I’ve been pleased with the new Canon S800, a six-color
printer that uses individual ink cartridges. My black and white infrared
prints have rich, deep blacks, and sparking highlights. With a simple
color adjustment I can choose between printing sepia tone or neutral toned
prints.
For anyone who has any experience with infrared film, shooting digital
infrared will seem like a dream come true. Being able to preview the
results in real time is critical to composing the most effective images.
For wedding photographers thinking of offering IR shots as an added
feature, digital allows instant results as well as the ability to shoot
color with the simple change of filter.
To see more of our own digital infrared work, and see a list of IR
resources, please check out
www.InfraRedDreams.com
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Is the Sony DSC-F707 Cyber-shot
the ultimate IR camera? |
Imagine a 5 megapixel digital camera with a simple switch
that moves the IR blocking “hot glass” out of the optical path, a camera
with an excellent electronic viewfinder, and even a pair of built in
infrared emitters to illuminate your subject in total darkness. Sound like
the ultimate IR camera? In low light conditions, the Sony DSC-F707 IR
abilities are phenomenal. Unfortunately, Sony has intentionally limited
its ability to work in normal daylight. Stung by sensationalist reports in
the media about how it’s infrared capable video cameras could see through
clothing, (some kinds of material, especially wet bathing suits, tend to
be somewhat translucent to IR light), Sony has limited the Cyber-shot’s
exposure range. When in “NightShot” (IR) mode, the camera will not adjust
it’s exposure to be shorter than 1/60 of a second at f2.0, thus greatly
overexposing in daylight. Combining an 88a infrared filter with neutral
density filters can compensate for this limitation, but it’s a shame that
this artificial restraint exists at all. Overall, this camera is a joy to
work with, opening up a whole world of nighttime infrared possibilities. |
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