Docteur Christophe: Stereoscopic shooting

How did I manage to catch the 3 dimensions of our World?
I had some fun sorting the different way to obtain a stereoscopic pair (see the page “Anaglyph, what a hell is that?”).
There are numerous manners to freeze the depth but I chose to describe only those based on stereoscopy. Thus I won’t speak in this page about lenticular network nor holography whereas they are used in some particular cases. You can have a look at that page.

Two consecutive pictures using a unique camera with optical axis parallel: “cha-cha” method.

This is the easiest method because it can be done with any camera including a single use camera. It consists in shooting two pictures, with the same parameters (exposure time, field depth,...) moving the camera side way between the two shootings while keeping the optical axis parallels. It can be improved by fixing the camera on a slide-bar in order to shoot both pictures on a perfectly parallel way. Click here to see my “homemade” slide-bar.

Two consecutive pictures using a unique camera with converging optical axis (Toe-in).

This is a variation of the previous method consisting in shooting the subject from two separate places. The principal advantage is, when you do not overpass some extend, a better control of the composition: no need to crop the borders of the image after shooting. Nevertheless, if you pass that limit, this method leads sometime to a total disaster ; especially when the background is far from the subject or when it is not homogeneous. In that case, you will have to play background clipping with your favourite image editing software! convergence is a method used a lot in 3D macro photography but also to get the depth from distant huge subjects: mountains, buildings,... In reality, when you say you shoot “cha-cha”, you often shoot converging.

One shot with a double lens camera.

The stereoscopic photography is something like 150 years old and numerous specific cameras have been proposed and still are being proposed: Vérascope, Realist, but also the Polaroid mini-portrait camera. The former one is not design for that use but able to. So many professionals, like Monsieur Jourdain speaking prose all his life without knowing it, shoot 3D without knowing it. Here, is my portrait as an anaglyph from an ordinary 4 colour passport photos.
With such a device, it is possible shoot 3D pictures of moving subjects because the two pictures are shot exactly at the same time.

Two pictures simultaneously using two cameras (moving subjects possible).

The shooting conditions are similar to the double lens camera with two advantages:
-Distance between the two cameras can be set thus modulating the relief effect.
-Any pair of identical cameras can be used.
In consideration of the two advantages, two inconvenients:
-It is quite difficult to obtain the simultaneous release of both cameras. 2010: It was the case few years ago, partly addressed by quite expensive dispositives such as Lanc Shepherd or Pokescope. Then, Masuji Suto released his “StereoData Maker (SDM)” (follwo the link for more details).
-The system could results quite bulky especially if it is made by coupling two SLR camera ! But real amateur are not afraid of that. They surely experiments the same sensations photography pioneers lived carrying their heavy view cameras. I am dreaming when I can afford it (2010 note, I am fully happy with SDM).

Use of a beamsplitter.

The goal is to lead the two images to the sensitive surface of a camera using a beam-splitting device: A set of mirrors and (or) prism carry two half-images to the camera or to its lens.
Advantages:
-It is possible to shoot fast moving subjects as the two images of the pair are taken exactly at the same instant.
-Usually, there is only one lens witch limits distortions between the two images of the pair.
Disadvantages:
-The device geometry should be very precise.
-The stereo-pair orientation is portrait.
Low price simple devices of that kind can be found, they are not high quality but give access to the stereo of the moving subject. This is the case of the famous Loreo (as an accessory for SLR camera).
Finally, it can be noticed that the vast majority of the stereo macro-photography visible on the Web have been shot with such a beamsplitter.

Twice with a flatbed scanner.

This is a bit silly, I found a Website explaining why simply moving an object on the window of a flatbed scanner it results a stereoscopic pair. I can’t remember the URL. By the way, I did not understand those explanations. So, I tried with my “posographe” and IT WORKS!

By flipping the object in front of a still lens (microscope).

In the area of small object, micro photographies can be obtained by slightly flipping the sample changing the observation angle.

There are probably a lot of other mounts witch adapt to each stereoscopic shooting case.

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Stereoscopic shooting