Re: Panasonic developing world's first intechangable 3D lens for Micro Four Thirds

Started Jul 30, 2010 | Discussions thread
Joseph S Wisniewski
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Sterobase, Panasonic, and binoculars...
In reply to RikMaxSpeed, Jul 30, 2010

RikMaxSpeed wrote:

A critical factor in stereoscopy is reproducing the viewpoint from each eye - typically about 10cm apart

Typically 65mm +/-12mm for humans.

  • there's no way this lens is going to achieve that - looks like 1 or 2cm apart at most.

I put it closer to 20-25mm, but that's still too small.

So things will look very flat, a bit like when you look through binoculars at something a long way off. (That's why the lenses on binoculars typically widen out).

That's not really true. Binoculars typically have magnifications of 7 or 10x. But the stereobase increase is only 2-2.5x, sufficient only for decent 3D at distances of 4-6m. Binoculars are typically used for subjects much farther away.

Binoculars typically widen out because they use Keplerian optics, positive objective, positive eyepiece. That gives them a wider field and generally higher optical quality than Galilean optics (positive objective, but a negative eyepiece). Among other things, Keplerians partially correct their CA, Galileans increase it.

But Keplerian optics produce inverted images, so a pair of Porro prisms invert each image. This means that the eyepiece isn't in line with the objective any more. For large binoculars, the objectives would literally collide if the prisms were oriented to bring the objectives closer together, and most people find periscope binoculars (where the prisms lift the objectives up, relative to the eyepieces) to be rather difficult to hold. So, they go outward.

Small binoculars typically have the prisms oriented to bring the objective lenses inward.

And small, expensive binoculars use roof prisms and the lenses end up in-line.

So is this just a worthless gimmick?

No. Given sufficient resolution, it's possible to take an image shot at one particular stereobase, and build either a multi-layer 2D or a 3D representation, adjust that representation to a new stereobase, and flatten it back to a new stereo pair.

There's more info on it over in this thread. You're welcome to come over there and join in.

http://forums.dpreview.com/forums/read.asp?forum=1000&message=35914938

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Rahon Klavanian 1912-2008.

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