Introduction to Stereo Photography

Stereoscopic photography creates photos with a sense of depth by capturing two slightly different perspectives, mimicking how our eyes see the world. In this introduction, I’ll try to cover the basics of how anyone can capture stereo photos.

How It Works

Our eyes are separated by about 65mm (the “interpupillary distance” or what we’ll call the baseline with photos). Each eye sees a slightly different view, and our brain combines them into a single 3D image. Stereo photography replicates this by capturing two images from slightly different positions.

How to Capture Stereo Images

Dedicated 3D Cameras

Purpose-built stereo cameras have two lenses at a fixed baseline (the distance between them). They capture both images simultaneously, which is essential for moving subjects. Examples of these cameras include the Fujifilm FinePix Real 3D series and the QooCam EGO.

iPhone Spatial Mode

Recent iPhones with dual rear cameras can capture spatial photos. The two lenses serve as the stereo pair. The baseline is small (around 12mm), which works well for close-up subjects but produces subtle depth at distance (Apple suggests subjects at three to eight foot distance). Another caveat is that the two lenses are of different quality which is not ideal to take identical photos for each eye, but in reality, it works quite well.

Cha-Cha Method (Sequential Capture)

For static scenes, you can take two photos by shifting your camera sideways between shots. This “cha-cha” technique requires no special equipment but only works for subjects that don’t move.

How to View Stereo Images

Anaglyph (Red/Cyan Glasses)

The classic approach: the left and right images are filtered through red and cyan colors and overlaid. Everyone has probably seen the classic cheap style of 3D glasses. Cheap glasses let you see the 3D effect, though color accuracy suffers.

Cross-Eye Viewing

By crossing your eyes slightly, you can fuse side-by-side stereo pairs without any equipment. Takes practice, at least for most people, but works anywhere.

Parallel Viewing

Similar to cross-eye, but your eyes look straight ahead as if viewing something distant. Works best with smaller images or a stereoscope.

The Google Cardboard made this popular and easy, it is basically a cheap box that you put your phone into and used software to show a split image to each eye, it worked surprisingly well.

VR Headsets

Modern headsets like the Apple Vision Pro, Meta Quest, or any VR viewer can display stereo pairs with full color and proper separation. Unlike Anaglyph viewing or 3D movie theater methods like RealD 3D that use polarized glasses, where they passively block half the light that goes to each eye, VR headsets show the full brightness and full color of their screens to each of your eyes.

Besides looking ridiculous wearing one and possibly cutting yourself off from the real world, this is the ideal way to view 3D content.

Understanding Baseline

The baseline is the distance between the two camera lenses (or positions). It determines how pronounced the 3D effect will be. It’s kind of like using a telescope or microscope, it gives us the ability to see in ways ours own eyes cannot.

Narrow baseline (minimal-30mm): Good for close-up subjects, portraits, macro

Normal baseline (50-75mm): Mimics human vision, natural-looking depth

Wide baseline (100mm+): Exaggerates depth, useful for landscapes and distant subjects

The 1/30 Rule

A common guideline: your baseline should be about 1/30th of the distance to your nearest subject. So if your closest subject is 3 meters away, a baseline of 100mm (10cm) works well.

Hyperstereo

Hyperstereo uses an exaggerated baseline—sometimes meters apart—to create dramatic depth in landscapes, architecture, or aerial photography. It makes distant objects appear miniaturized while creating striking depth separation.

Next Steps

I’ll write a future post on editing software for what to do once you’ve captured the images.