what exactly does a 3D camera do? Photos are printed on 2D paper or viewed on a 2D monitor. Can anyone post an example of what exactly is 3D?
Well, TK already did that. As far as "what exactly is 3D", it's just taking pictures that correspond to your left eye view and right eye view (either a dual lens camera, or moving a camera to get both views) and then, somehow, "routing" those two images to the appropriate eyes.
The most common way involves printing two images, side by side on "2D paper" or a "2D monitor". This pair of images on the same paper or screen is referred to as a "stereo pair". You use any one of a number of gadgets commonly called "stereoscopes" to get the images to the proper eye.
Oliver Wendell Holmes created the first popular and widespread viewer of this type, way back in 1860, 150 years ago. Holmes used a 3x7 cardboard card to mount the pair. That put the centers of the two images 3.5 inches (89mm) apart, and the human eyes are only 2.4 inches (62mm) on average. Although we can turn our eyes inward (cross eyed) we can't turn them outward (walleye, like the fish, LOL). So, Holmes used "prism lenses" to angle your view outward, and allow you to focus on the card 8 inches away.
People still print in that format, and view using modern replicas of the Holmes viewer. You can buy these completely assembled from a number of vendors, or as kits, or as plans. The folks who sell plans also sell the hard to find stuff, like the prism lenses.
Since 4x6 is such a popular photographic print size, a modern stereo industry sprung up around that format. Loreo "mini" and "maxi" viewers are probably the most popular "modern" sterescopes. They are also based on prism lenses.
I go through a lot of maxi viewers: I typically include them with any 3D work I shoot (commercial, portrait, or TFP).The optical quality is pretty good (occasionally, they have a run with "wavy" lenses, if you get those, send them back for an exchange). It will hold about a dozen cards in the lid when you close the viewer, so you can have a little "slide show" with you.
http://www.berezin.com/3d/mini_viewer.htm
The drawback of prism lenses is that prisms not only change the direction of light, they also break it apart into colors, so prism lens stereoscopes produce a "rainbow smear" on images. Sir Charles Wheatstone created the "periscope" style 3D viewer (1840, 20 years before Holmes) that doesn't have the prism lens problem, but was considerably more expensive and harder to maintain. Even today, there are still companies building replicas of his viewer.
Here's a modern Wheatstone viewer. The periscopes give it an effective 5.5 inch (140mm) interoccular, so it looks inward on any stereo pair smaller than 11 inches wide. This is quite useful. I use one of these when I just want an "anywhere" grab it style viewer. I use it for
- proofing 4x6 cards or Holms (3.5x7) cards as they come out the printer, before they get cut up for their particular viewers.
- books that have 3D images, mostly compilations of older ones.
- viewing side by side stereo pairs on small monitors. The Wheatstone is good for pairs up to about 14 inches wide, so you can view full width on laptops or small LCDs like a 17 inch.
Some people actually print two 4x11 pairs on an 8.5x11 (A4 is fine, too) sheet of paper, and view with a Wheatstone as their primary way of viewing 3D. Not my cup of tea.
For any of those purposes, they can't be beat, their optical quality is excellent. They are a "two trick pony", not the best on-screen viewer, not really compatible with any screen over about 17 inches, unless you have the stereo pair in like a 16 inch window. Not the best print viewer. But quite servicable for both. I keep on ein my laptop bag.
Warning: All modern Wheatstone viewers that I have seen have small lenses, set close together. They only work on relatively small faces. The ones I own are set up for a 56mm interoccular and are a touch uncomfortable with my 61mm. They won't work with anyone with a 64mm or larger interoccular.
http://www.berezin.com/3d/wheatstone.htm
(disclaimer, I have no commercial connection to Steve Berezin. He is one of several 3D equipment vendors. He's competent, courteous, and has never given me reason to switch vendors. I'm linking all these images of viewers from his site, so I thought it was only fair to also link the products).
wizfaq 3d
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Rahon Klavanian 1912-2008.
Armenian genocide survivor, amazing cook, scrabble master, and loving grandmother. You will be missed.
Ciao! Joseph
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