Re: [photo-3d] Chromatic aberration

["John A. Rupkalvis" <stereoscope@xxxxxxxxxxxxx>]

If the aberration were equal in each eye view, the only problem would be a
general degrading of the images near the edges of the field.

However, with many viewers, especially card viewers, the eyes are not
looking through the exact center of the lenses, but somewhat off-axis.

Since card viewers and some other types as well make use of the wedge prism
effect of intentionally mounting the lenses off center (for divergence on
formats that have centers wider than normal eye-spacing), the chromatic
aberration is opposite for each eye.  Thus a red-blue shift in the left eye
is seen as a blue-red shift in the right, resulting in a visual differential
commonly referred to as "retinal rivalry".

How objectionable this may be is determined by several factors, including
the focal length of the lenses (affecting the conjugate distance ratio, and
thus the amount of "spread" in the color shift), whether the image is black
& white or color, and the subject matter itself (is there any material of
interest or with high detail near the edges?).

JR

----- Original Message -----
From: "Dr. George A. Themelis" <drt-3d@xxxxxxx>
To: <photo-3d@xxxxxxxxxxxxxxx>
Sent: Monday, February 05, 2001 2:52 AM
Subject: RE: [photo-3d] Chromatic aberration


> >>The detriment of chromatic aberrations is not only
> >>simply seeing extra colors (blue/orange fringing),
> >>but also severely impacting on the 3-D effect.
>
> >It just occurred to me that my message of a few days ago
> >might not be clear. I didn't mean to say that it would not be
> >immediately apparent to George! What I meant to say
> >is, "This doesn't apply to George." To George, it's mighty
> >clear.
>
>
> Actually, to George, it is not clear at all!
>
> Exactly why and how does the chromatic aberration
> impacts the 3-D effect?
>
> (I did not read Boris' original message very carefully.)
>
> Any optical defect will affect the 3-d viewing if it
> has a different effect in R and L images.  Can someone
> give a bit more insight on how chromatic aberration
> will do that?
>
> George
>
>
>
>