[Updated with more information]
Utilizing Panasonic’s depth from defocus mapping system, these cameras are now capable of readjusting your focus after the fact with a simple touch of the screen.
In order to capitalize on this new feature, one will have to download the new firmware, turn on the new “Post Focus” feature in the menu tree, and enter “4K Photo Mode”. Once enabled, you will start by capturing your subject or scene like normal and then be able to review your stills for adjusting. Here’s where the magic happens; glide your fingers across the touch screen and select the point you want the camera to focus on. You can take this step further by punching in 5x on your subject and using a slider paired with focus peeking to fine tune your selected focus point.
Will this work for video?
We’ve been looking into how this works and it seems it actually uses the camera’s 4K video ability. Essentially, when a picture is taken in Post Focus mode, a short 4K film is made, with the focal point sweeping through from near to far during the short duration of the shot.
The technique uses Panasonic's 49 area DFD (Depth from Defocus) auto focus technology, and the 4K abilities of the cameras targeted by this firmware update.
Images in Post Photo mode are taken at 30 fps at 3840 x 2160 resolution (i.e. around 4K).
We assume from this two important things. First, this is not a technique that can be used for video - because it already uses video to create a single, refocusable shot. And secondly, if you move the camera while the shot is being taken, the viewpoint of the camera will change as you select your post-focused picture. Panasonic says that "The Post Function is best for non-moving subjects".
Updates for the GH4
Another interesting thing to note here is that while the GX8, G7, and FZ300 firmware will be ready to go shortly, the GH4 update will be trailing behind by a few months. It's interesting because as we know, the GH4 is an older camera. It looks like Panasonic is going to continue to upgrade the GH4 despite rumours circulating around its eventual successor, the GH5. This is a welcome feature in a long list of tools packed into these tiny cameras.
So it seems that while this is a very clever implementation of a "capture a still photo from a 4K video" technique, it is not comparable to the "Lightfield" technology used by Lytro, and more recently by Light. But what it does show is that there is an important future for 4K (and, even better, 8K) in still photos. This update may be the start of something very big in the joint evolution of still and video photography.