Quote Originally Posted by AgX View Post
A multiple exposure technique using staggered focussing is used in analog macro photography too.

However, not complete images are overlayed. Instead only parts of the object corresponding to the plane of focus are photographed. This is achieved by lighting the subject by means of slit lighting in the plane of focus. After each exposure the subject is moved by the width of that lighting.
Wow, I did not expect that. But it sounds very complicated.