A technique used in one of our recent videos was to animate still photographs, and turn them into 3D moving images. This effect is often called the “2.5D” or “Parallax Effect” and is a great way to easily breathe dynamic life and movement into otherwise motionless stills, and to help them mesh better with moving video. However, it does take some time and technical skill to achieve.

The basic premise of the effect is to take a still 2D image, and split it into its separate background, mid-ground and fore-ground elements, and then move each element past each other to give the illusion of a 3D space.

Next time your in a car, look out of the window. The close pavement and streetlights will be moving past the window much faster than the buildings across the street, and the hills behind those houses will be moving even slower still as they are further away. This is called ‘Parallax’ and is what is being mimicked with this effect.

The first step is to choose a suitable image. You need to look carefully at its properties as not all images will work for this method. Look for good separation between fore-ground, mid-ground and background elements and ideally you also want a reasonably deep depth of field with quite a bit of the image in focus. This will make separating the elements from each other easier.

Below are tow images, one that will work well the other not. What makes the image on the left suitable is the highly separated elements within it.  As you can see with the image on the left, the two rocks will become the fore-ground layers, the two students the mid-ground, and the sea as a final fifth layer for the background. The image on the right is not suitable because there is very little distance or separation between all the students and the ground. It would be extremely difficult to separate them into defined, individual layers.

This image works well becuae of the distinct separation between the fore, mid and backgroundscattered around the shore at Bigbury. ***For use in promotion of the Marine Biology degrees only*** *** Local Caption *** Marine, Ecology, beach, animals, rock pool, felid trip, biology, Coastal Ecology, Oceanography.
The lack of separation between fore,mid and background means this image won’t work well.
This image works well becuae of the distinct separation between the fore, mid and background
This image works well because of the distinct separation between the fore, mid and background

After a suitable image was selected, it was taken into Adobe Photoshop. Using the quick selection tool, all of the individual elements were cut out into independent layers. Then using the clone stamp tool, “missing areas” were painted back in, such as the sea and part of the girls legs.

Into this group of layers: (show the five distinct layers from Ps)Individual Image Layers
The five distinct layers in Photoshop, cut out and then clone stamped

These layers were then taken into Adobe After Effects (compositing software) to be arranged within 3D space. Below shows the arrangement of the layers in 3D space, you can see the background layer (the sea) is much further back from the camera than the students and the rocks. Because of this, when we track the camera forward towards the ‘scene’ the Parallax effect becomes apparent.

Layers with Camera ScreenShot

The final stage of this effect was to add a slight animation to the students, to give the sequence even more of a dynamic feel. This gives the impression the scene is actually a slow motion video as the elements appear to move very slightly. This is done using a process called Puppet Pinning which warps a still 2D image using points that you define as pivots. The resulting motion is very subtle, and works best if used sparingly. Moving the image too far results in unrealistic warping of the subject. Less is definitely more in this case.

This gives you only a brief overview of the process; it can take a long time and become very complicated with certain images as many require background elements to be carefully repainted with the clone stamp tool in Photoshop, but the effort is worth it and with practice becomes an extremely powerful way to add production value to your video.

And finally, here you can see the transformation of this particular still into a fully fledged Parallax motion sequence. Enjoy!


If you are interested in learning more about this technique, here is an in-depth and well explained video tutorial

You can also watch this excellent example to get your imagination flowing


2 thoughts on “Slow motion from a single still image (the 2.5D parallax effect)

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