Many years ago I realized that taking a stereo photograph of a stationary object is as trivial as taking a picture, locking the settings, moving your camera a few inches to one side, and taking the same picture again. The first shots I took I used a tripod and a ruler laid against the front of it and it worked out fairly well. Unless you have a controlled environment, though, this is all really elaborate and burdensome. Some years later, I thought to myself, “How precise do I really need to be?” Turns out you can get a fairly decent 3D effect freehand. It’s pretty simple, actually. Stand squarely in front of your subject with your feet about two feet apart. Favor your left foot. Frame your shot and lock the settings, Take the pic. Shift your weight over to your right foot and take the shot again. Mission accomplished.
Choosing a Subject
You’re going to be taking two separate pictures, one after the other, so the first thing you need to consider is that the subject must be static. That pretty much rules out animals and children, but planes, trains, and automobiles are still good options. Ideally there shouldn’t be any movement going on in the background, either. This makes outdoor shots challenging, but not impossible. Avoid windy days and busy roads and you should still be able to get a good shot.
The second consideration is how interesting your subject is going to be. Choose a subject with a strong presence in the foreground and an exciting shape. Again, planes, trains, and automobiles tend to be good choices, but if you’re experimenting around the house, you can also try musical instruments or toys. String instruments can be especially good. The strings tend to pop nicely.
Finally, avoid very small subjects. You won’t get the depth of field you need for a nice sharp 3D picture if you’re only inches from your subject.
Setting up the Shot
Once you’ve chosen your subject, it’s time to compose. You have options here, but there are a few don’ts. Compose your shot as you would any other, but be careful not to crop anything that’s in the foreground. For example, don’t cut off the nose of the plane. Doing so creates a jarring effect at the edge of the picture. Also try to stick to a safe zone around the edges of the picture where nothing too dramatic is going on, depthwise.
Shooting against an open backdrop with a clear horizon gives a pleasing effect as the 3D view will show the ground and sky dropping away into the distance, but fifty feet or so along, the parallax is so small that you really won’t be able to perceive a whole lot of depth
Taking the Shot
This is where it gets tricky. You’re going to want to take two shots in rapid succession while locking the camera settings. Both shots need to have the same focal length and exposure level. The easiest way to do this is to let your camera do the thinking, but only let it think once. Most point and shoots will not refocus between shots if you keep the shutter button halfway depressed. In theory, the exposure time could vary between the two shots, and this is something you need to look out for. Usually you’ll be fine. The two exposures will be similar enough that the light level will be nearly identical.
A better option, if you have it, is to set up the shot manually. Most dSLRs will let you switch from aperture priority to manual without losing focus and exposure settings. Doing this will guarantee both shots look the same.
A note on choosing an aperture: I’ve found that a fast aperture doesn’t work as well as you’d expect. Instinctively I thought that the focus blur would enhance the perception of depth, but in reality it seems to interfere. Choose a small aperture and you can’t go wrong.
Okay. You’re almost set. It’s time to take some pictures. Assume a sturdy stance with your feet about two feet apart, directly facing your subject. Shift your weight slightly to your right leg. Look at your subject through your viewfinder and align some noticeable part of your subject with a cross-hair. It doesn’t need to be the center cross-hair. If you’re using a composition grid, you have four to choose from. Point is, find a fixed point on your subject and line it up with something on your viewfinder. Now, depress your shutter halfway. Your camera should focus and lock exposure settings. Take the picture, but be careful not to lift you finger all the way off the shutter. Keep it halfway depressed. Now slowly lean to one side by shifting your weight to your left leg. If you’re using a regular zoom, you want to move about 4-5 inches to the left. Be careful to keep your camera horizontal. Make sure your marker is lined up with the exact same point it was on the previous shot and push off the second shot.
Creating the 3D Image
Now that you’ve made the shot, go download Stereo Photo Maker. Start it up and select “open left/right images”. Now it’s time to get the alignment taken care of. SPM will take care of the minor misalignments you might have accidentally introduced when taking the picture, so it’s best to just let it do its thing. Select “adjust -> auto-align”, or just press alt-a. Once the images are aligned, you can tweak the depth. Select single image “view -> flashing” and use the left and right arrow keys to adjust the parallax. The point where The two images are in the same place will appear to be on the same plane as the viewing surface, while anything that was in front of that will pop out of the screen. Make sure that nothing that is in front of your viewing plane is cropped.
Now that your stereo shot is set up, it’s time to render it in a way the eye can see. The easiest rendering to visualize is called the wobble technique. It involves creating an animated gif that rapidly switches between the two eyes. The mind ends up extrapolating the depth information. This technique has drawbacks though. For one, any excessive depth info is just jarring – the effect is easily ruined by exactly the kind of shot you’re going to want to take. The files are also cumbersome. Animated gifs are not known for their portability. Having said that, to create one of these, simply select “file -> make animation gif” You’ll be able to see in the preview whether or not the effect is any good.
A better way to create a 3D image that’s viewable without any special glasses is to place the two images side-by side and view them cross-eyed. It’s not hard to view one of these once you’ve worked out the technique. Fundamentally it’s the same technique used to view those old 3D steganographs – you remember the ones: a seemingly random pattern of colored static that resolves into a 3D image of a schooner if you look at them just right – you simply relax your eyes and slowly cross them, as if you were focusing on something in the middle distance between the screen and your face, until the left and right images merge. It’s kinda headache inducing, but it works well. These are easy to create, too.Just save your project as a stereo image. Some people like having a bit of space between the two images or small aligned dots on the bottom or top of each image to help the viewer line them up. I’ll leave that up to you.
Your most sure-fire option to create compelling 3D that anybody can see on the cheap, however, is by creating an anaglyph, to be viewed with those old-fashioned 3D glasses you might have lying around. If you don’t you can pick up a few pairs dirt cheap from Amazon. There are two primary types: red/blue or green/magenta. SPM will do either and these can be veiwed either as prints or on screen. Of course, the cost is that you lose color data and have to use goofy glasses. Honestly, it’s best to just go the black & white route if you’re using these things.
One final tip – if you ever find yourself looking at an image that’s just not right in a jarring, instant headache kind of way, you probably swapped the left and right images. SPM’s “swap left/right” button in the toolbar will fix you right up.
Follow Us! 