Yep, it's a well-known phenomenon. Decades ago I had a summer job with a company that did stereo aerial surveys on large-format film. If you reversed the left-right orientation of the stereo pairs, the topography was reversed- river beds stuck up, mountains were depressed. It was weird! I noticed the same thing with my Hale-Bopp stereo pairs. For those, rather than taking two shots simultaneously from widely separated geographical locations, I just used shots separated by an hour or so in time. During that time, the earth moved quite a distance in it's orbit, as well as the comet in it's orbit, which gave the necessary displacement relative to the background stars. The stereo effect was the same as simultaneous shots. When reversed left-for-right, it appeared that the comet was behind the stars, instead of in front of them. A bit OT astronomically, but on-topic as far as stereo imaging. These are rather remarkable shots. I posted this link some years ago but here it is again for recent list-serve subscribers: http://www.lenticulations.com/#1 On Thu, Feb 28, 2013 at 4:39 AM, Patrick Wiggins <paw@wirelessbeehive.com>wrote:
I forgot to mention that sometimes when I use the cross eye method to view the pairs one pair makes the Moon look like a sphere sticking out towards me while the other pair has the Moon looking like a concave dish.
Anyone else seeing that?
Apparently any 3D effect is an illusion as I get the same thing when looking cross eyed at two copies of the same image.