[3D Tutorial] – Stereo Photography

A basic 3D Stereo photography tutorial

Introduction
Part 1 - History & Theory
Part 2 - Create a basic 3D picture
Part 3 - Refining the technique
Part 4 - Getting serious about 3D Stereo photography
Part 5 - Further reading...

[3D Tutorial] – Stereo Photography - Part 5

Part 5 – Further reading

There are some very active yahoo groups that showcase 3D stereo photography and 3D-Anaglyphs

http://tech.groups.yahoo.com/group/anaglyphs/
http://groups.yahoo.com/group/photo-3d/

For additional reading I would redirect you to these sources which have additional reading material and most comprehensive cross-reference sections on Stereo 3D:

http://www.rmm3d.com/3d.encyclopedia/index.html

http://www.dddesign.com/3dbydan/3dlinks/linksct.htm

http://www.rmm3d.com/misc/links.html

http://info3d.home.att.net/StereoResources.htm

[3D Tutorial] – Stereo Photography - Part 4

Part 4 – Getting serious about 3D digital photography

As I said in the beginning, 3D photography is not new. There are still a lot of people that are passionate about it (as you will see from the reference links later). As you would expect, there are also much better ways of getting "proper" 3D photos than the humble cha-cha anaglyph presented in Part 2. Here are only some of the alternatives...

Film & convert


Use a stereo 35mm film camera and then scan the fill photo pairs into digital before creating the anaglyphs. It's a much longer process, but using an older camera with two lenses means that you can actually take 3D shots of moving themes too, wihtout being restricted to still life. Although not cheap, you can still find good secod-hand Kodak and Realist cameras on ebay for reasoable amounts of money. Two-lens SLR's do exist, but they are more rare to find and cost a lot more...

Digital 3D Stereo Camera



Fuji recently announced the FinePix Real 3D W1 camera, which is a pure digital stereo camera, and managed to get most of us interested in 3D photography drooling... However the prices are still very high (around UKP £450 at the time of writing this - Nov 2009), so for most of us it will remain a dream toy.

Two-camera Rigs

Several people have invested time and effort creating 2-camera stero rigs, using two normal digital cameras. Although not the easiest contraptions to carry around, nor cheap, when they are synchronised correctly, most will do an excellent job.




Split beams

An alternative approach, uses mirrors and/or prisms to generate two stereo images on a single frame, using a single camera. Devices such as a tri-delta rig and Loreo Lens in a cap can fit on your normal camera, with reasonable results.



A special case of artistic licence - 3D from 2D

Finally, it would be wrong of me not to mention one of the most ingenious pieces of software I've come across relating to 3D. It's not "stereo" photography in real sense, but it allows you to reconstruct very credible 3D versions of 2D images, through photo manipulation. The software is called 3D Gugle Pro and I would invite you to look at some of the work that it's designer has done on some classical masterpieces, in this gallery. Even if you don't attempt it yourself, it's well worth the look!

[3D Tutorial] – Stereo Photography - Part 3

Part 3 – Refining the technique

Selecting the right themes

Some themes work better for 3D than others. Especially where the stereo-pair of pictures are not taken at the same instant but in sequence (e.g. cha cha). Generally, themes that work well are static and don't change between the two shots. Animals, people, waves and windy trees are a disaster. Scenery, bridges and still life, work much better.

Also, try to select themes that have a strong dimensional character or perspective. Leading lines such as walk paths or bridges work very well. Pictures with multiple depth levels (foreground, mid-ground, background) also work well. Pictures that are by their nature two-dimentional (a wall, a painting, a far away mountain range) don't lend themselves to 3D work.

Tripods & supports

One of the fundamental principles in creating anaglyphs, is that the pictures are taken from the same vertical plane. so ideally, the two shots should be taken with the camera at the same hight and pointing in the same direction and only shifting horizontally.

There are third-party "slide bars" that allow you to mount your camera on a dripod and shoft it horizontally. If you are interested in buying one, just click on the picture:



However, here are some other ways you can achieve the same effect. If your tripod allows you to move the central column to a horizontal position, you can usually shift the camera along horizontally:



If you are lucky enough to have a set of bellows (or can get hold of one!) with a separate focus rail, then mounting the camera sideways gives you the identical functionality of a slide bar, with a lot of control. (The one shown here is from a Minolta series II bellows):



If you are a crafty DIY man or woman, then you can always make your own of course... Click on the picture to see how.



Keeping it consistent

Last tip: consistency between the pictures in the stereo-pair is important! To get the best results you should have the same focus and the same exposure between the two shots. Once you have mounted your camera on your tripod and slide bar, take a test shot and make sure your camera has focused correctly. If your camera allows you, switch at that point to manual focus (MF) and you should retain the same focus point.

Similarly with exposure: take a few test shots to determine the correct exposure for your shot. Then make a note of the reading, and set your camera manually to the same setting for the two pictures. This is especially important when shooting outside where the light is changing constantly. It's better to have a pair that is consistently over/under-exposed, than one of each! (hint: If the sun is playing hide and seek in and out of the clouds, wait for a few minutes to let it stabilise one way or the other, between taking the pictures!)

[3D Tutorial] – Stereo Photography - Part 2

Part 2 – Create a basic 3D picture

Doing the cha-cha

Let me quickly introduce you to the cha-cha method. No, not the dance, although that’s where the name comes from. In order to create a real 3D image, you must always start with two different pictures. Typically taken about 6.5 cm apart (same as the distance between your pupils). So the cha-cha method is a quick and dirty way of taking two shots with your camera, by standing with your feet firmly planted on the same spot, but shifting your body weight from one leg to the other – shift to the left, cha, shift to the right, cha! Get it? Good.

Don’t worry too much at this point about the accuracy, but try as much as possible to not twist or swivel the camera. Just keep it on the same vertical plane and move it along horizontally between the two pictures. Also try to shoot something static and avoid subjects that would have changed positions between the two shots…

So now you have a “left eye” and a “right eye” picture. Download them on your computer and let the fun begin…

Now, you need a pair of red/cyan glasses (sorry can’t avoid that!) and a piece of free software: Download and install a piece of software called “Stereo Photo Maker (SPM)”. It’s free in its basic form and will do the job very nicely. Other ones (e.g. AnaMaker) are also available and worth exploring later, but I’m sticking to SPM here as that’s what I’ve got installed on my machine.

Once SPM is up and running, use File - Open Left/Right Images to open your “left eye” and “right eye” pictures. SPM knows it’s a stereo pair and will display the pictures side by side. If you choose the option Stereo - Color Anaglyph - Color (red/cyan) from the menu, or just hit F7, it will give you immediately a basic anaglyph version of the two. Now, if you look at it through your 3D glasses, unless you have been spectacularly accurate in your cha-cha method (unlikely), it will probably just look a mess and give you a headache. Don’t worry, we will fix that!

The next step in the process is Alignment. Remember the experiment with the pencil in part 1? The brain can judge the distance, between the front and the back, because your two eyes have a fixed position to each other. When you moved your camera about between your cha-cha shots, chances are that quite a few things changed, so we need to bring the cyan and the red pictures back in alignment.

The simplest way to "fix" the picture is to just hit the “auto” button (or select Adjust - Auto Alignment from the menu or Alt-A) and SPM will do the most of the work for you. If you want to do the basic alignment manually, just identify one of the objects in the foreground of your picture (like the tree in this case) and use your arrow keys to shift the two images until that part of your picture meets up.

Congratulations! You have made your first Anaglyph 3D picture! Use File - Save Stereo Image to save it as a JPG and upload it to your favorite site to show-off to your friends:-)

If you explore SPM a bit more, you will dscovervarious tweeks to allow you to improve the picture further before you save it. Here I have used the sharpening function and selected the "No compression ghosting" option in the save dialogue.

Once you have mastered the basics of creating 3D images, read the following sections for some tips and tricks to improve your technique and how to spend some serious money if you really want to get into stero 3D properly! :-)

If you use these tutorials, please leave me a comment and a link to your work. I would love to see other people's 3D work!

[3D Tutorial] – Stereo Photography - Part 1

Part 1 – History and theory

This part is a bit academic, but it will give you a basic understanding of why things work the way they do. I recommend that you read it, but if your fingers are itching to try something, skip to Part 2.

Brief History of stereophotography

The roots of stereo photography go as far back as the end of 19^th century.

The technique was popularised in the early ‘20^s, which saw several different stereo cameras and viewers mass produced, using glass plates.

It then declined until the late ‘40^s when a new range of 35mm stereo cameras produced and later with toy viewers like the ViewMaster™.




Digital photography has made 3D photography relatively easy again and although we still don’t have a digital 3D camera available, other techniques have been developed. (see Part 4)

Basic Principles

Stereo photography is based on one fundamental principle: That our two eyes, see a slightly different picture, and the brain is using the discrepancy between the two, to assess depth and distance. This is not the only mechanism the brain uses (others are movement, focus, shade, etc) but it is the most fundamental one.

The easiest way to illustrate this, is with a simple experiment. Hold up a pencil, or even your finger in front of your face, and by closing each eye in turn, observe how the pencil is positioned against objects further away in the background:

Left Right

If we align these pictures on the pencil, you will notice that the images of the background are shifted from each other. Conversly, if the background is aligned, then the pencil appears double. The brain performs the same assessment, moving from one to the other, and can therefore “guess” the distance between the two layers (panes)

Stereo photography exploits this principle by combining two different pictures in a way that each eye is presented with a different view, similar to what each eye would see if they were actually looking at a 3-dimentional scene. The brain then is “tricked” in assessing the distance, creating the illusion of a 3D image.

Assuming you have these two images available, there are a number of ways of presenting them. The most basic is just simply pitting them side by side with a divider in the middle, and allowing each eye just see one of them. Another is to have special viewing glasses (like binoculars, but with prisms). Another yet, is forcing your eyes to look cross-eyed, until the two images are forced to align in your vision.(You can try it with this image. It works, but don't complain to me if you get a headache!)

All of these are possible and have their merits, but the most common approach for digital photography is the Anaglyph method.

The Anaglyph method, is based on altering the tint of each picture of the stereo pair with a different colour (typically red/cyan) and then overlaying the two stereo images. You need to use a special pair of filtered glasses to view the picture, but these are available for a few pennies. With this method, the left eye sees only the red picture through the red filter, while the right eye, through the cyan filter, sees only the cyan picture.

A similar method of overlapping images is used for movies, but instead of using red/cyan glasses, it uses polarizer glasses, with one lens polarized horizontally and the other vertically. Unlike Anaglyph, it only works with projected light, but it has the advantage of not interfering with the picture's colours.

Now that we've covered the basic principles, in the next part we will create a very basic 3D Anaglyph picture.

[3D Tutorial] – Stereo Photography - Intro

Intro - How to create 3-Dimensional pictures with your normal digital camera.

I got my first “taste” of stereo photography as a toddler. My grandfather (who died before I was born) was a stereo photographer, and left behind a legacy of stereo glass plates, a couple of cameras and a beautiful stereoscopic viewer. As a kid, I’ve spent hours fascinated by this giant Viewmaster!

While I was shooting film, I never considered doing my own 3D, but digital cameras opened up a whole new world of possibilities. I am not an expert in stereo photography, there are people out there who have much more experience and much better understanding of the theory behind it. In this tutorial, I hope I can give you some basic techniques that you can use to generate some primitive (but real!) 3D photographs.

In the next few sections, I will show how you can create real three dimensional photographs using your normal digital camera.