Instead of using multiple images focused at different points to extend the depth of field, can I also reduce it?
Does a technique exist to reduce focal length by stacking multiple images that are exactly the same except for focus? An example of a situation one could think would be mimicking extreme shallow depth of field as in a medium format close portrait capture. Indeed, my intended focus stacking method would also not be simple, but theoretically possible.
Here is an example image of Katja Schuurman.