How to take 3D photos using any camera

Most people are not aware of the fact that you can take two ordinary photos, put them next to each other, and see the scene that is depicted in three dimensions, depth and all…

Demystifying the sorcery that is “stereography”

This is not as weird as it sounds if you think about it. You see in three dimensions because you have two eyes. If you close one of them, you see a two-dimensional image. It is only when you put the images from both eyes together that you can see the depth of the scene in front of you. By making yourself more or less cross-eyed (in essence, moving the images across each other), you can appreciate which object is closer to you, and which is farther away.

The reason why you see depth is because you have two eyes at a set distance apart. That distance, which is something like 10cm for humans, makes us especially good at judging depths of around 0.5–10m (the distances at which our ancestors had to perform dexterous activities crucial for survival such as hunting, gathering, and fighting). Everything that is closer is hard to discern, and that which is farther away will seem as though it is at the same distance (two-dimensional). Seeing two images which are a set distance apart is called “parallax”. The figure below illustrates this concept.

The two eyes are looking at a scene containing a nearby box and a faraway cloud. The two eyes see the scene differently because they are viewing the objects from different angles. One can simulate this using a regular camera by taking one photo corresponding to the position of the left eye, and one for the position of the right eye. Then one puts the photos next to each other, with the photo for the right eye on the left, and the photo for the left eye on the right. For an example, see the photo of a Venetian gondola below:

I’ve placed the two previous objects in this photo as well. As you can see, their relative positions in the two photos differ. If you look at the photo on the right, the box – which is closer – is located more to the right of the cloud – which is farther away – than in the photo on the left. This shows that the photos, although identical at first, have been taken with a slight parallax. If you look back at the first picture, then you can appreciate that the right photo in Venice corresponds to what the left eye sees.

How to make a stereograph

Take a photo
Move sideways with the camera/phone perfectly vertical/horisontal.
- Any angulation will make the photos unusable for stereography.
- Move more the larger and farther away the object you want to show is.
- For best result, center the object of interest
Take another photo
Put the photos next to each other, with the right photo on the left side and vice versa.

How to see regular photos in 3D

So far so good… Here comes the hard part. To see the image in three dimensions, you need to have a decent amount of coordination in your eyes; you need to make yourself cross-eyed, and look at the photo on the right with the left eye, and vice versa for the right. Essentially, you need to overlap the images and fuse them into one. This can be very hard, and require hours of practice for some people, while others can do it right away. Rest assured, if you put in the practice, this will open up a whole new world for you. Next time you travel the world and see something you want to remember, rather than taking a picture of it, you can take two pictures and experience it once again. Or, take pictures of a loved one and have the visual experience of them sitting in front of you.

From having taught others how to view stereographic photos, I’ve developed a method to simplify the learning process:

Put the stereographic image in full screen mode (so as not to have any distracting objects around).
Start by using smaller photos, or sitting farther away.
- The smaller the distance between the photos, the less you have to cross your eyes, which is the hard part.
Put your hands up vertically in front of you, with a small distance between them.
Align the edges of the hands with the edges of the two photos.
- The right eye should see only the left photo, and the left eye should only see the right photo. See images below for example.
- Start by closing the left eye and aligning the right eye and hands to the photo on the left.
It is extremely important to hold the head completely vertically, as the photos won’t align otherwise.
Identify something that you can easily see in both photos, preferably something that is vertically aligned (such as the metal part at the front of the gondola).
Start crossing your eyes until the two objects overlap completely.
Keep your eyes in that position until the muscles in your eyes relax and the focus becomes clear.

At first this will be difficult, the image will be blurry, and you may get a headache. However, after some time, your eyes start to relax, and the image will become as crisp as the original photos, with the small difference that you suddenly feel as though you are standing in the middle of Venice.

Trust me, the practice will be well worth it!

Here is a great first stereograph to practice with. Try aligning the building in the middle or the yellow sign…

What would the world look like if you were a giant or an ant?

By changing the size of the parallax one can get different depth perceptions; a larger parallax increases depth perception at larger distances, and a smaller one increases perception close-by.

For example, one can take two photos that are 50m apart. This huge parallax will make you blind for objects that are within 500m. However, it will give amazing depth perception at distances of 5-10 kilometers. One can simulate this parallax by travelling with an airplane; take a picture through the window, wait a couple of seconds, then take another one. The pictures will be some 100-200m apart (with the first image representing the left eye if you are sitting on seat A). When overlapping the images and viewing the scene stereographically, the otherwise huge clouds will look like small fluffy balls.

After a lifelong experience of viewing scenes through a parallax of 10cm, it is truly mind blowing to see the world around you at different scales. Have a look at the example below that I took during a transatlantic flight (which is at a much higher altitude than shorter flights). One can appreciate how the clouds reach upwards in a way that is not possible when looking out of the window using the small parallax of your human eyes.

Honey, I shrunk the kids?

By decreasing the parallax, one can make small objects appear large. This miniature landscape is from a museum in Paris I visited a couple of years ago. Even though the figures are tiny, they look as though they are normal-sized, and everything outside looks huge.

Stereography galore

Here is a collection of some other stereographs I’ve made over the years, withs gems from Rome, Milano, Florence, Venice, the Vatican, Amsterdam, Belgrade, Paris, Warsaw, Milwaukee, and somewhere in the sky…