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Yes. With a single lens the centre of each "bunch" of rays (left
and right) MUST cross in the optical centre of the lens. If they
don't they will be bent by the lens and destroy the image...
The unavoidable problem with this is - as has been stated - the
bunches of rays Cannot be parallel.
On 10/04/2021 21:18, Antonio F.G. via
On Fri, Apr 9, 2021 at 03:09 PM, Depthcam wrote:
> By the way, such mirror design could produce
parallel shots if the angle of the mirrors were adjusted for
I was not sure about this, but nothing like making a drawing of a
"perfectly" parallel mirror adapter, with mirrors exactly at 45°:
Actually, no. This will only work if a mirror adapter is
mounted on a set of two lenses - as is the case with the Leiz
Stemar or the Zeiss Stereotar C. When you mount a mirror
adapter on a single lens and keep the optical axes parallel,
each side is viewing one side of the scene - just as if there
were no adapter. In order for a left and right image to be
recorded of the same scene, the optical axes MUST be
The rays from a point at infinity arrive in parallel to the
mirrors, and they send them to the lens in parallel as well.
Therefore the lens prints a single point in the sensor. This is
exactly the same as if the mirrors were not there.
It seems that the way to get two separate L&R images of the
point is to deviate the mirrors somewhat away from 45°.
But I am still not sure whether this implies necessarily
convergence of the two optical axis (may need another drawing:-)