What's it all about?
I have been interested in photography for a long time, and have recently taken an interest in stereoscopic photography.
You have probably seen those Red and Green or Red and Blue '3D' pictures sometimes printed in books, viewed through thosecardboard spectacles with coloured lenses. The pictures look something like this:
These are called anaglyphs. Each one contains two images, one for the left eye and onefor the right, all jumbled up together.The image to be seen by the left eye is coloured red, and the right eye sees the other colours.The glasses separate the two images and the brain does a pretty reasonablejob of combining them into one stereoscopic colour image.
More sophisticated stereo techniques allow the viewing of full colour images,by presenting the images for left and right eyes individually, like this:
The two pairs of images above look the same at first glance. However, the top pair is in parallel format, where the image for the left eye is on the left, and the image for the right eye is on the right.
Conversely, the bottom pair is in crossed-eye format, where the image for the left eye is on the right, and the image for the right eye is on the left. This is often used, since with a bit of practice, many people can see these images without a viewing aid by crossing their eyes till the two images become three, with the middle one appearing in stereo. It is also possible, with some practice, to view small parallel images without a viewer by relaxing your eyes.
Stereoscopic Viewers
There are a number of types of viewer that enable you to view stereo images more comfortably. I use a PokeScope which is a simple folding viewer containing two prisms. It allows you to view parallel stereo images. (Note: I haven't found a UK distributor for the Pokescope. I bought mine from Berezin Stereo Photography Products in the USA.)
Left, Right, Left, Right...
So, apart from anaglyphs, there are two main formats of sterescopic images on the web, parallel and cross-eyes. I think the latter are more common, which is a problem to users like myself, with a PokeScope that can be used for parallel images only.
Some kind people post images in sets of three, e.g
Right - Left - Right
or
Left - Right - Left
You can view such images parallel or cross-eyed by looking at the first and second pictures or the second and third pictures.
However, this is fairly rare, and you can easily miss out on viewing images on the web because they are the wrong format for your viewng method.
I thought about this for a while, and decided that a browser extension might be able to solve this problem. This is how I came up with the idea for ViewDouble.
ViewDouble Firefox Browser Extension
The ViewDouble browser extension is an add-on for the Firefox web browser.
It allows you to view parallel images in cross-eyed format and crossed-eye images in parallel. It also allows you to zoom in and out too.
Read all about it on my ViewDouble pages.
Apology to Internet Explorer and other browser users: sorry but this only works on Firefox. However Firefox is free and a great browser. You can download it from the Firefox home page.
Producing Stereoscopic Photographs
I have used three methods to produce stereo photos:
- The cha-cha method
- Pseudo-stereo from monoscopic photos
- Loreo 3D Lens in a cap
The cha-cha method
This method involves using a normal camera to take a picture of a scene, moving the camera a few centimetres to the left (or right) and taking a second picture of the same scene.
The first picture becomes the image for the right eye, and the second for the left (or vice versa).
Once at home, you can process the images with software such as StereoPhoto Maker or 3D Combine to combine the two images into one stereo image.
Pseudo-stereo from monoscopic photos
This method is rather fun, though no doubt it upsets the purists!
Starting with a standard monoscopic photo, I use PhotoShop Elements to create a greyscale depth map of the scene. Things that are far away are coloured black, things in the foreground are white, and all shades in-between.
3D Combine has a tool to create a pseudo 3D image from the original photo and the depth mask. I run this, which gives me a raw stereo image.
Then the retouching comes into play, tidying up the image and making up bits of image where background not part of the original was revealed.
With care, the result can be quite convincing!
Loreo 3D Lens in a Cap (LIAC)
The latest acqisition is a Loreo 3D Lens in a Cap, which is a sterescopic lens to fit an SLR.
This has the big advantage over the cha-cha method that the pictures are taken in one go, and so moving subjects (such as people) are captured successfully.
I am using the 3D Lens in a Cap (T) with a Samsung GX-10 SLR.
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