More stereo posts are appearing in forums, more members are sharing 3D photographs, viewing them, becoming more curious about the format and having a go themselves.
In my stereo threads members have asked about varied aspects of 'shooting stereo' and viewing the results. But the answers are scattered among the threads. The purpose of this thread is to offer a one-stop service for members who may want to know more about the 'how to' of stereo photography. I shall do my best to answer your questions or link you towards the right direction. In doing so I hope to assist you in literally opening up a new dimension in your photography!
There is much I could choose to begin writing about so I shall begin with answering the most direct and simple of questions. Should you want to know more please post your enquiry into this thread and I shall answer as best I can ...
So, what is stereo photography?
Stereo photography is the combining of two similar images to create a third which offers the perception of depth. The two images mimic what each eye sees in the manner we view the world. Therefore, people who can see only with one eye cannot, unfortunately, perceive depth or recreate it in stereo photography.
How is a stereogram viewed?
There are two ways of viewing a stereogram, namely freeviewing or by using a viewing aid.
Freeviewing itself means looking at a stereo commonly in one of two ways: parallel or crossed. The former is the most natural inasmuch the left eye looks at the left image and the right eye looks at the right image. A central image appears giving stereo depth. The effect is impressive. There is one significant limitation with this method. The width of the the stereogram cannot be wider than the distance between the viewer's pupils. Trying to get your eyes to splay further left and right than they are is not recommended! The consequence of this is Parallel stereos tend to be small.
Crossed stereos on the other hand can be viewed in sizes which can be very large indeed -- even poster sized if you wished. Crossed stereos are those which are commonly posted to POTN. In this method the left eye looks at the right image, the right eye looks at the left image and a central image fuses to give stereo depth. With practice this can be done almost instantaneously and effortlessly. The sense of depth is also very impressive though slightly shallower than in Parallel freeviewing.
Novice freeviewers often report sensations of strain at first. Frequently this is the result of straining the eye muscles by crossing eyes too vigourously. This can be made worse by viewing a monitor which is too close. For best results sit 2 or 3 feet away and practice little and often. Some people acquire the knack at once, others have to persist with regular practice -- just as I did -- before their first stereo pings into depth! The watchword is 'relax' and you will achieve your aim in the end.
Anyone with corrected vision can freeview!
There are various mechanical aids available on the market to assist people in viewing Parallel stereos. These vary in price and sophistication. Before mastering P freeviewing I used the Pokescope. It makes viewing a cinch. Another benefit of this device is it allows the viewing of stereos which are too big to freeview.
There is another popular stereo format which requires a viewing aid and that is called "anaglyph". I have only seen one in the forums. This is the fuzzy looking red and blue image type often found in magazines. Spectacles with a red filter for one eye and a blue filter for the other eye are needed for viewing. The great benefit of anaglyph format is that very large images can be viewed and they can be zoomed around giving the viewer the sense of being immersed in the scene -- and all in stereo depth!
Thanks for reading and if you want to know more about any aspect of stereo photography, please, feel free to ask!!