I can only speak for my Nikon 50mm f1.8 Ai-s manual focus lens and the Olympus Pen-E PL7. The K&F Concept® Nikon - M4/3 lens mount adapter ring for Nikon AI lens is well suited for this. The adapter sits firmly and without play on the lens and can be easily attached to the m4/3 bayonet. 

You would need to check the filter size of you 25mm lens, and then order accordingly. 

1. You could consult us or search the mount information online
2. You could find the mount information on your instruction book when purchase the lens/camera
3. The mount information may be showed on front of the lens, side of the lens, rear of the lens or on the lens cap, usually it is a 2 or 3 letter code such as: CN, FD, OM, MAF, NK, N/AIS or F/AX

 

hello FD-M4/3 suitable Canon FD Lens and Micro 4/3 M4/3 Mount Camera .we have confirm your panasonic lumix gx85 is M4/3 mount,so the adapter ring can work with your camera 

The adapter will mount the lens and you will be able to use it manually. However, my copy of the adapter does not allow the lens to be fully mounted all the way until it clicks into place. It doesn't quite make it, but it's still very solidly mounted. Also, the manual aperture linkage doesn't work properly (on my copy, at least) so exposure is controlled only by shutter speed and/or ISO. You will be able to manually focus and zoom the lens but no VR, of course. It will be a frustrating experience. Instead, get a 14-140 Panasonic zoom if you can afford it!