Infrared Stereo Images by David M. Lee

Note: Scans of images reproduced on the computer screen in the proper size for 3D free-viewing do not have enough resolution to represent the quality of the original prints. In many of the scans presented here, scanning artifacts give the photos a "grainy" appearance that is not present in the original prints, and much of the beautiful subtlety of the originals is lost in these reproductions.

Stereo images consist of 2 photographs made at the same time. The right eye sees the right image and the left eye the left image. Many stereo photographers use stereo cameras that have 2 lenses which are about 2.5 inches apart (approximately the separation of the eyes.) I use 2 cameras so that I can vary the separation of the cameras to get optimal depth, since scenes vary in how far they are away from the photographer. If a scene is far away and one uses a stereo camera there will be little depth in the image. The camera separation in these images ranges from 4 inches to 200 feet.

The cameras I use are medium format twin lens reflex cameras carefully matched so that the left and right images are as close to identical in size and exposure as I can get them. The images were made with pairs of Ricohflexes, Rolleicords, or Yashicamat 124G's. I also have a pair of 4x5 cameras (made by me out of wood) with factory matched Schneider Symmar 120mm lenses (I have used some Kodak HSI 4x5 film and will eventually print some images with it).

In order to manage the separation of the cameras I use a 2 foot long "U" shaped aluminum bar on a tripod. When the cameras are more than about 8 inches apart I usually attach cords to the ends of the bar down to the tripod legs for greater rigidity. The determination of the camera separation is based on a formula, the simplified form of which is 1/30th of the distance from the near point in the scene to the cameras.

The film is Konica 750 IR. This is an excellent film and, while slower than the Kodak, it is much finer grained. I also prefer the anti-halation backing on the Konica because I want the images to be as sharp as possible. I wouldn't mind seeing what the effect would be if it were sensitive to longer IR waves, as Kodak is, but I'm happy with it just the way it is. One complaint I've heard is that the film is too contrasty. I would agree if I didn't have the ability to vary the development to get the contrast I wanted. If you give it as much development as you would a normal film it is almost unprintable, especially in bright sunlight. My first tests were with HC110 developer and I ended up with a dulition of 1:100 from the bottle (the usual dilution is 1:31) for 5 minutes at 68 degrees. Now I use TMAX developer at 1:15 (the usual is 1:4) at 75 degrees for 8 minutes for open shade (which is my usual lighting situation). I use an Exposure Index (the user's ASA) of 8 metered with a Minolta spot meter (not through the filter) and use #25 red filters.

I believe that it is preferable to have everything in focus in a stereo image (if I don't like some element that is in the scene, then I don't make the exposure) so I usually use small apertures (occasionally as large as f/11). Since 99% of my images are made in open shade or overcast light my exposures are usually in the seconds, and sometimes as long as several minutes.