Here is a review of the Panasonic LUMIX DMC-FZ300 camera’s Post Focus feature by Maarten Heilbron, in the following video:
In a November 2015 firmware upgrade for the FZ300, G7 and GX8 cameras, Panasonic added the post focus feature, enabling photographers to select a focus point after shooting. This review demonstrates the feature with real world examples and show how to use it for focus stacking.