To start with we need a Stereo Pair of images.
These can be made on any camera device including Phones, Compact Cameras, SLR's and Camera pairs.
The advantage of this app is that after you have taken the first image and you move 2 1/2 inches to the right, it displays an overlay so you can position the second shot at your choice of point of focus. The down side of the app is the delay between taking the two shots making live action very hard to photo in 3D.
You can get add-on "Beam Splitters" (Amazon £12) that attach over your phones lens that allow you to take a stereo pair in one shot. This fixes the lag between taking images but the small size of the attachment means the paralax is small limiting your to short range images (6 foot max)
This can be done in many ways, the quickest is to shift your balance between the left and right foot between shots. Another way is to use a small jig to allow you to slide the camera to the right between shots.
Like the Android app above this method of using a single camera makes it only good for still life subjects.
The best software to finish processing your stereo pair from a compact camera is "Stereo Photo Maker" (click to download), This freeware app will pre process the images allowing colour and contrast adjustments, conversion to HDR, aligning the images and outputing them to all the various 3D formats. There are loads of easy to follow tutorials for Stereo Photo Maker on their home page https://stereo.jpn.org/eng/stphmkr/
COMPACT CAMERA PAIRS
With just a little practice, you will be able to triger the shutter on both cameras at the same time, making both still life and action shots easy and so removing the limitations of the previous methods.
While this does involve the expence of two compact cameras, batteries and memory cards this need not cost the earth. I bourght 2 second hand, 16MP matching cameras off eBay, with rechargeable batteries and a memory card, for just £10 each.
Good choices for an auction camera are the Samsung ES series (like the ES71) or PL series (like the PL170) but any compact that takes 5MP or better, along the same form factor will work. Buy at auction NOT Buy it Now to get the best price.
With a pack of M6 Nuts and Bolts from Wilko (£2) and an off cut of wood you will be ready to go.
As above, the best results for 3D images will be produced by "Stereo Photo maker".
Having tried these methods with my SLRs, forget the idea and go the twin compact route. Its cheaper, easier, faster and produces better results for very little efort.
We will do this one first. From 3dSteroid or Stereo Photo Maker take a copy of the two (left and right) images, in this case Dave-l.jpg and Dave-r.jpg (below)
Now you need to go to https://ezgif.com/apng-maker/ and upload the two images and apply the following settings before you click [Make APNG!].
After some processing time (1 - 2 mins), as the AI creates an additional 16 interleaved images, you will be given an animated result that does this.
Without the AI generated additional frames it looks like this
There are tutorials and video training and other resources that will be posted here ASAP