Thursday, November 12, 2009

[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!

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