it takes two images to make 3d images, a left image and a right image taken at the exact same moment, (literally: left eye-right eye). But they are not identical. it is the slight differences between the two images that corresponds to the different perspectives of the left and right eyes. these slight differences are called stereo parallax. stereopsis is your ability to perceive parallax as stereo depth. it all relates to the spacing between the center of the eyes. For Humans, this distance is about 2-1/4". Anything wider is hyper stereo. since we cannot see in 3d beyond 200 meters, hyper stereo is useful for landscapes and distant features. It adds a sense of depth not normally possible by the eyes alone. basically your stereo depth of field is expanded. if hyper stereo is taken to far you get what is  described as the doll house effect , a more or less surrealistic view, as if you are looking through the eyes of huge giant. Many of the images on the Enchanted Rock 3d cd AND OTHER CDs are hyper stereo ( to a mild and pleasant degree) and are great examples of this effect. you don't just look at the pictures, you look into them. You will be able to see individual elements in the pictures as if you ARE there. so, basically the brain does all the work sorting all this information and creating 3d images with depth in your mind that allow you TO DO, in your day to day life, such things as threading a needle, driving your car,  reaching down to pick up a small object, driving A NAIL WITH A HAMMER or anything Else THAT REQUIRES JUDGING DEPTH . TRY TO DO THESE WITH ONE EYE COVERED.

viewing 3d images

there are three basic types of 3d images, as for viewing on the internet.  anaglyphs, stereo pairs and cross-eyed stereo pairs. Anaglyphs are tinted in red and blue and are viewed with the  well knownRED/BLUE 3D GLASSES FOR VIEWING ANAGLYPHS red/blue 3d glasses. They are basically two COLORED images merged into one - red for the left eye and blue for the right eye. the red and blue lenses of the glasses cancel out the colors so that they become invisible to your eyes leaving only, the 3d image visible. inferior red-blue glasses will sometimes produce ghosting, which is some visible residual  red and blue color that can be quite annoying. the key to viewing anaglyphs is the glasses. American paper optics "in your face" cardboard framed 3d glasses are the best. They can be shown in full screen for the best effect and realism.   there is a good chance some visitors may have a pair of glasses.  Stereo pairs are viewed with various stereo viewers such as handheld stereo viewers, view master slide viewers, and more recently, the poke scope and a whole host of others too numerous to mention. and MOST ARE EXPENSIVE and not suitable for mass distribution as are the paper glasses.  since most visitors to this site do not have viewers, stereo pairs are not shown in the galleries. cross-eyed CROSS-EYED PERSON  stereo pairs need no viewer and can be viewed with a little practice. check our other 3d format page for examples.