This documentation covers the features and functionality that is included in 3D Camera version 1.2. A lot of this material also applies to 3D Camera Lite.

For a quick video introduction, watch our 4-minute 3D Camera Video Tour.

3D Images

Human binocular vision (seeing with two eyes) enables us to view the world from two slightly different perspectives: a left-eye view, and a right-eye view. The fusing of these two views by our brain enables us to perceive a third dimension called depth (or distance).

To create a 3D image, two photos are taken from slightly different perspectives. Then, the left image is presented to the left eye, and the right image is presented to the right eye. Various techniques are used to present the correct image to each eye, and 3D Camera supports two of the most common: anaglyphs and stereograms.

3D Camera also has built-in support for “wigglegrams.” However, while wigglegrams can simulate a 3D effect, they are not true 3D images, because both the left- and right-eye images are presented to both eyes.

Instructions

Creating a photo with 3D Camera requires three general steps:

1. Capture: Obtain a left-eye image and a right-eye image using either the built-in iPhone camera or by selecting two saved images from your photo album.
2. Adjust: Modify the alignment of both images to improve the 3D quality and control how “deep” the photo looks. Also, swap the left- and right-eye images if they are reversed. Then, view the 3D photo as an anaglyph, stereogram, or wigglegram.
3. Share: Save the 3D photo to the photo album for later use, or send it directly to friends on Facebook and Twitter (via Twitpic).

As a handy reminder, these steps are displayed each time the app starts. To skip the reminder and jump directly to the capture phase, disable the Introduction Screen in the app settings.

Capture

The capture phase is when the left- and right-eye images are obtained. This is accomplished by taking two photos with the built-in camera or by selecting two saved images from the photo album.

Camera

To use the built-in camera, two photos must be taken. The first photo is the scene as viewed from the left eye, and the second photo is the same scene as viewed from the right eye. Like human eyes, the two photos should be spaced with some distance between them. Also, like human eyes, the two photos should be aligned horizontally. That is, when the camera is moved after the first photo, it should move horizontally—not vertically.

Another way to think about horizontal alignment is to imagine a straight line that crosses the screen and touches the top of an object in the first photo. The top of the object should also touch the same imaginary line in the second photo. To make it easier to align photos during capture, 3D Camera overlays a translucent version of the left image while taking the right.

It is important that the camera stay pointed straight ahead for both photos. Don’t rotate or “toe-in” the second photo. It is useful to imagine that the camera is firmly attached to a rail or a bar. The second photo should be taken as if the camera was simply slid to the right. Often, a tripod, stand, railing, table, etc. can be helpful.

A rule of thumb is to move the camera 1/30^th of the distance to the closest object in the photo. For example, if the closest object is 60 inches away, the camera should be moved 2 inches (60 / 30 = 2) horizontally between photos. Or, simply remember to move very little for close-up photos and much more for distant photos. For distant mountain photos, the camera may have to move a few feet.

3D Camera automatically saves each photo to the Camera Roll so they be used elsewhere or re-loaded from the photo album.

Photo Album

Instead of using the camera, left- and right-eye images can be loaded from the photo album. The photos can come from any source—they do not need to be 3D Camera photos. However, they are still subject to the techniques and guidelines described in the Camera section. Both photos must be the same size.

To load photos from the album, touch the Cancel button on the camera view to see a thumbnail list of images. First, select a left-eye image; then, select a right-eye image.

Adjust

After obtaining left- and right-eye images from the camera or photo album, a screen will show that allows adjustment and viewing of the 3D photo.

Align

The first step is to align the left- and right-eye images. This can be used to fix any horizontal alignment issues that were introduced during the capture phase. Alignment also controls how deep the 3D photo appears.

Imagine objects that “pop out” or are “in front” of the iPhone screen, objects that are at the same depth as the screen, and objects that are “inside” or “behind” the screen. First, choose an object to position at the same depth as the screen. This object is often the main subject of the photo, though that is not a requirement. Touch and drag the right-eye image so that the object overlaps exactly with the same object in the left-eye image. Tip: A light touch on the screen can be easier to control than a heavy touch.

To check progress, switch to one of the other views to see how the 3D photo looks. If the images need more work, simply switch back to the alignment mode and continue the adjustment.

To control the depth of the 3D photo, remember that moving the right-eye image more to the right causes the scene to recede into and behind the screen. Likewise, moving the right-eye image more to the left causes the scene to pop out.

Most newcomers to 3D photography like things to pop out of the screen. While this is fun, the same people are often surprised by how good 3D images can look if everything is behind the screen.

Window Violation

While the intricacies of alignment can quickly become an advanced topic, it is helpful to understand Window Violation (or “WV”). A WV occurs when any edge of the left- or right-eye image intersects or cuts off an object that appears to be in front of the screen. The brain has trouble fusing a 3D photo that contains a WV, and something will look “wrong.”

WV issues can be avoided completely by keeping foreground objects away from the edges of the left- and right-eye photos during the capture phase.

To fix a WV after-the-fact, align the left- and right-eye images so that the intersected object appears at or behind screen depth using the alignment techniques described earlier.

Swap

If the left- and right-eye images have been switched—perhaps because they were captured or loaded in reverse—touch the Swap button to exchange them. Note that the images will need to be re-aligned. Swap is also used to toggle the stereogram viewing mode between parallel and cross-eyed.

Anaglyphs

An anaglyph image is made by combining the left- and right-eye images into a single 3D photo. When viewed through color-filtered glasses (commonly red and cyan), the red filter over the left eye prevents that eye from seeing the red image, and the cyan filter does the same for the right eye. The brain fuses both images together and perceives a single 3D scene.

3D Camera supports two anaglyph modes: grey and color. As the name implies, a grey anaglyph produces a grayscale version of the 3D photo. Because the filters in the glasses can interfere with colors like red and cyan, a grey anaglyph is often a good solution. It’s worth trying both modes to see which one looks best.

For 3D enthusiasts, there is an app setting to choose which method is used to create the color anaglyph. See the app settings section for details.

Stereograms

A stereogram image is created by positioning the left- and right-eye photos side-by-side. Because they don’t require color filters and can be viewed with the naked eye, stereograms are full color, full quality images. Stereograms can be arranged in both parallel and cross-eyed configurations, and 3D Camera displays the current mode in the title bar.

Parallel

In the parallel mode, the left-eye image is on the left, and the right-eye image is on the right. This is the original presentation arrangement, but most people have trouble viewing them without a special viewer. With practice, some people can learn to keep their lines of sight parallel and view the two images simultaneously. This is called “free-viewing.”

One technique involves focusing the eyes on a distant object then sliding the stereogram into the line of sight. If the lines of sight are kept parallel while shifting focus to the image, parallel free-viewing will occur.

Cross-eyed

In the cross-eyed mode, the left-eye image is on the right, and the right-eye image is on the left. It is generally easier for most people to view a stereogram that is cross-eyed than one that is parallel.

One technique involves focusing on a finger placed half-way between the viewer and the stereogram then moving the finger back and forth until the two images overlap to produce a third. Then, carefully shift focus from the finger to the third, 3D image.

For additional free-viewing tips and techniques, see How To Freeview Stereo (3D) Images.

To switch between parallel and cross-eyed stereogram modes, touch the Swap button. Remember that the left- and right-eye images may need to be realigned after a swap.

There is an app setting to control the size of the black border that surrounds the left- and right-eye photos. The setting ranges from a complete elimination of the border to a border that is relatively thick. Thick borders can be used to reduce the amount of image overlap and interference that appears when viewing stereograms.

Wigglegrams

Wigglegrams can provide a sense of depth, but they are not considered true 3D images, because they do not simultaneously present each eye with a different perspective. However, wigglegrams are easy to view, and they can work with just one eye. By quickly flipping between left- and right-eye images, the brain can use persistence of vision and parallax to sense depth.

Wigglegrams work best with small movements. As a result, it’s best to be subtle when moving the camera between images.

Share

After a 3D photo has been adjusted, it can be saved for later use (printing, e-mailing, etc.) or shared with friends on Facebook and Twitter. To save or share a 3D photo, touch the Action button.

Save to Album

Touch Save to Album to save the 3D photo to the Camera Roll. Like other photos, they can be synchronized and downloaded to a computer and shared via e-mail, printed, posted to a web site, etc.

Note that wigglegrams cannot be saved using this technique, because the iPhone has no support for saving animated images. However, because the original images are saved, it is easy to quickly reload and recreate the wigglegram.

Send to Facebook

To send a 3D photo to Facebook, touch Send to Facebook. Then, enter the Facebook account information, and touch Connect to upload the image. Note that Facebook does not support animated image uploads, so wigglegrams cannot be sent at this time.

Send to Twitpic

To send a 3D photo to Twitter via Twitpic, touch Send to Twitpic. Then, enter the Twitter username and password, and touch Send Photo. The image will be resized based on the Twitpic Image Size app setting, then sent to Twitpic and announced on the Twitter feed. Note that Twitpic supports all 3D Camera photos, including wigglegrams.

App Settings

To configure 3D Camera app settings, touch Settings from the iPhone home screen. Then, choose 3D Camera from the list.

Introduction Screen

The introduction screen that explains the 3D Camera steps can be disabled by switching this setting to Off. By switching it Off, 3D Camera skips the introduction screen and jumps immediately to camera mode, ready to take the first photo. This setting defaults to On.

Image Size

This setting determines the size of the photo that is processed by 3D Camera, and it is configured as a percentage of image size. If the left- and right-eye photos come from the iPhone camera, this represents a percentage of the camera image size. The options are 25%, 50%, 75%, and 100%, and the default setting is 50%.

As a mobile device, the iPhone has less memory and power than would be expected from a laptop or desktop computer. To process a left-eye image, a right-eye image, and a blended 3D photo all at once requires a lot of memory. Depending on the apps that have been run prior to launching 3D Camera, only some of the memory in the iPhone may be available. Larger image sizes may require that memory is cleared before launching the app. This can be accomplished with a utility like Free Memory or by restarting the iPhone.

Color Method

The color method setting determines the algorithm that is used to blend the left- and right-eye images into a color anaglyph. Choices include Full Color, Half Color, Optimized, and Red/Blue, and the default setting is Full Color. Examples of each method can be seen in the Anaglyph Methods Comparison.

Stereogram Border Size

This setting controls the size of the black border that surrounds the left- and right-eye photos in a stereogram image. Moving the slider all the way to the left eliminates the border completely, while moving the slider all the way to the right makes it as thick as possible. A thick border can often reduce the visual interference between images.

Twitpic Image Size

This setting controls the maximum size of images that are sent to Twitpic. Choices include Large (1,024), Medium (800), and Small (640), and the default is Medium (800). The value in parenthesis is the maximum number of pixels that is allowed in the largest dimension.