Zacuto has a new Z-Finder Pro designed for the Panasonic GH3 thanks to a GH3-specific Gorilla Plate that attaches to the bottom of the camera.
The GH-3 Z-Finder Pro has a 2.5x magnification and diopter for fine-tuning focus. If you already have a Z-Finder Pro or Jr., you can just pick up a Gorilla Plate and frame for the GH3.
The Z-Finder Pro for the GH3 retails for $395. The GH3 frame and plate kit runs $129. More details on Zacuto’s website.