Nikon D100 Infrared Photography
This webpage shows how to use the D100 for infrared photography. This
isn't the definite website on infrared digital photography. It's meant
to show that the D100 can perform this function easily.
Filtering:
Infrared is light of a longer wavelength than we can see. Different
Infrared (IR) filters have different cut-off levels to filter out light
smaller than a certain wavelength. I have chosen the Hoya R72
(also search for hoya 72r on the internet) filter in 52mm for my 50 1.4
AF-D lens. It seems to be a popular and reasonably priced filter for
this size. The 72 designation means it blocks light shorter than 720nm.
(This is the edge of what we consider visible light). Filter price seems
to increase exponentially according to your filter ring size, so if
you're just experimenting, you may wish to get a smaller filter for a
small practical prime lens.
General Procedure:
Because the D100, like most digital cameras, is meant to capture visible
light, you may notice some minor suprises in how certain colors or
shades render. You will defintely notice you need a longer exposure.
Handheld photography is only possible outdoors with high ISO settings
and fast lenses (f2 or faster). I use manual exposure, take a test
photo, and look at it on the LCD screen to roughly evaluate the
exposure. This is one of the conveniences of digital. Autofocus
continues to work much to my surprise.
Composition:
This approximates what you will see through the
viewfinder with the IR filter on. You can not see the composition through
the viewfinder. If shooting handheld, you can take a shot and check the
LCD screen to see if your composition was as expected. If using a tripod,
you can take the filter off for focusing and composing, replace the
filter, and capture the image. In outdoor scenes, blue sky will appear
very dark, and green foliage light. Clouds will be more dramatic.
Experiment and practice until you have the ability to see a scene and
predict how certain parts will show in IR. I'm pretty new at it and am
still enjoying the suprises.
Camera Settings:
When taking a photo, I use RAW to capture the images with as many bits
as possible. Much of the range that the camera is capable of is not
utilized. We have filtered out most of the visible range. The image will
likely be converted to black and white later.
This is an unaltered image like you might see on the LCD screen and
upload to your computer.
This is the final image - altered by converting it to grayscale and
adjusting the levels.
The steps to convert the image to a greyscale image are nothing
revolutionary. I'll use NikonView and Photoshop here, as they are pretty
common. Open the RAW file in Photoshop as shown below.
Convert the image to grayscale and 8-bit. If you have extremely gradual
tones over a large area, it may make sense to do this step after
adjusting the levels.
Adjust the levels.:
Use your artistic senses here. This is not
complicated photoshop stuff. Photoshop elements can do this stuff,
as can many shareware/freeware programs on a variety of operating systems.
The levels command shows and permit adjustment of the
scale of the range of shades present in the photo. As an adept user of
your digital camera, you may have noticed that different exposures
produce different histograms on your camera's LCD screen. This is just
the opposite. You can alter the histogram to change the exposure of the
photo. Underneath the histogram, there are three pointers. The black one
sets the boundary for blacks, the white one sets the boundary for
whites. The middle one rarely needs adjusting, but it alters the
midtones without changing the highlights or dark shadows. If you move
the black pointer to the leftmost utilized portion of the image
histogram, the darkest part of the image will change from gray to black.
If the white pointer is moved to the right utilized portion of the
histogram, the bright parts of the scene will be whiter. I have moved
the white pointer almost but not quite to the right part of the
histogram. This means nothing in the scene will be pure white (washed
out white).
If you used a higher ISO setting when capturing the images, there
will be some noise/grain present. A certain amount of grain seems
natural in many forms of black and white photography and will likely
show up in your images (like you'd expect with Tri-x) . An
Unsharp will enhance the grain slightly making it look more like
film. If you used a tripod and shot with a lower ISO speed, there will
be less noise and a smoother looking black and white infrared image
(like you'd expect with an aerial photo or other large format image).
In this case, unsharp would probably enhance actual image details rather
than noise/grain.
Resize, save, and upload. Backup your files, etc...
I use Gallery to organize
my uploaded photos. At my site,
you will see some other infrared photography with this
camera/lens/filter combination starting with the 2005 galleries.
Links:
|