The Advanced Art of Stop-Motion Animation: Digital Cinematography: Part 2
One way to focus on the photo subject is to shoot your scene with convergence on the point where you want the middle ground. This simply means that in addition to the camera sliding back and forth, the camera is angled slightly inward in each side. It would be like two eyes crossing towards each other slightly to focus on one point. The mechanics involved to shoot with convergence are more costly because the slider not only needs to move the camera back and forth, but also turn the camera inward towards the subject. In addition to technical end of figuring this out, the end results are pretty much configured there on set, with little room for adjusting in post. The other option, favored by most for stop-motion production (including on Coraline), is to shoot parallel, meaning the camera is simply pointing straight ahead at the set while capturing the left- and right-eye images. Shooting parallel allows you to play around with the alignment in post, creating more freedom of choices for how much stereo you want to create. As far as your camera settings, you can do things however you would on any other set, although keeping a wide depth of field, with everything in focus, will tend to enhance the stereo effect.
When you have left- and right-eye images shot and want to view them in 3D on your computer to test the 3D effect, the simplest method is to create an anaglyph image that can be viewed with a pair of red-blue 3D glasses. The two images can be layered over each other in Photoshop, each on its own separate layer. Hide the left-eye layer; then for the right-eye image layer, double-click on the layer in the “Layers” window to bring up the “Layer Style” window. Under “Advanced Blending” are three checkboxes for the red, green, and blue channels of your image. Check off the “Red” box, and you will notice a color shift in the image to a bluish tone (Figures 4.30 and 4.31). Click “OK,” and when both layers are still visible, you will see a double image and can move the right-eye layer around to find the alignment you want. Viewing this anaglyph image with your red-blue 3D glasses will show it in eye-popping 3D (Figure 4.32)! The same principle of creating an anaglyph image by turning off the red channel can be applied to an entire image sequence in After Effects, along with other options for adjusting the channels for the desired effect.
When shooting in stereo, this obviously complicates the workflow of your digital images since you will have two different versions of each frame of animation you capture. For this reason, it’s a good idea to have some kind of a system for storing these images in two separate folders, ideally while you are shooting. It’s possible to shoot all your images in a row and sort through them later, selecting every other frame and copying them en masse to separate folders. However, if your software allows for automatically separating the left- and right-eye images, that might make things easier.