Replacing the WX970 and VX870, respectively, the two camcorders differ physically in two primary ways: the WXF991 has a viewfinder and a second camera on the LCD door.
When Panasonic introduced its first 4K consumer models last year, it was odd that the $1,000 WX970 lacked a viewfinder; its replacement has one.
You can run the camcorders off an AC adapter and plug-in headphones.
Panasonic continues to use a jog dial (press to select mode and turn to make adjustments) for its manual exposure controls.
Like last year's models, these support HDR movie (HD-resolution only). It works by recording 30p video at 60 frames per second and alternating slower shutter-speed frames (for better shadow detail) with higher shutter-speed frames (for better highlight detail).
Panasonic's Twin Camera feature works by capturing a second stream of video from this rotating camera on the LCD door; only the WXF991 offers this in the 4K models.
Panasonic has updated the design of the wind shield on the microphone by adding a noise-reducing material between the microphone and the metal net, and it's changed the shape of the net for better wind travel.
Like most camcorders in its class, these have a cold (i.e., unpowered) accessory shoe.
The view from above.