In the interest of full disclosure I have owned the Panasonic G85 for about six months now and have used it to shoot over 10,000 images ; from stage work to landscapes and portraits, as well as using it to shoot several hours of 4K video. I am conversant with every control and menu setting on this camera. I have owned and used the 40mm lens for over 32 years and have shot many thousand images with it as well. I paired the two together to see what effect the camera's lack of anti-aliasing filter would have when combined with this much older lens. A lens originally designed for a half frame of film. I wanted to see just how sharp a file the combination would yield.
The handling of the lens is superb. It functions well on the G85 and the focus magnification makes fine focusing easy and quick. If you are stopped down to a middle aperture you can use the focus peaking in the camera with confidence. Today I was shooting most of the images in downtown Austin to ascertain whether I felt the wider apertures (f1.4, f2.0 etc.) were usable with a modern camera like the G85.
Final image focused on the S in "signature" with the lens set to f1.4.
The image has been sharpened in post.