How to separate figures in foreground from background

[Corey Sandler]

I often see an effect in documentary films where they separate figures in a PHOTOGRAPH in the foreground from the background, simulating an exaggerated 3D image.

I'm looking to do this effect on image stills, not animation.

I can't seem to find the tools to do that in Photoshop; all I see are ways to simulate 3D on an illustrated object or text.

Appreciate being pointed in the right direction.

[c.pfaffenbichler]

Please post an image. 

You may want to look into tutorials on clipping and masking. 

https://helpx.adobe.com/photoshop/using/making-selections.html

https://helpx.adobe.com/photoshop/how-to/select-mask-hair.html

[Mylenium]

Cinemagraphs use simple parallax trickery, which has nothing to do with real 3D. It's just layers moving around. The rest is mundane stuff liek creating cutouts for the layers and patching up the resulting holes in the background images.

Mylenium

[Bojan Živković]

Is this effect you are looking for?

[Corey Sandler]

Not at all.

Talking about an old photo with people in foreground, and I want to put some distance between them and the background.

[c.pfaffenbichler]

And again: Please post an image. 

How would you imagine to manifest that effect without motion? Blurring the background?