I mostly do photography using Nikon gear. When it comes to video I use the Panasonic GH5 and adapt my Nikon lenses via adapter. The adapter does not have any electronics. So Im stuck to manual focus (which is perfectly fine) and also I cant change the aperture of the Tamron 70-200mm G2 since it has an electronical aperture. When I use the Tamron 70-200 F:2.8 on this body it gives me an equivalent of an 140-400mm F:2.8 (which is awesome!). However Im thinking whether I should get the Nikon TC14E II teleconverter for my photography stuff. I came across the question if this teleconverter would work on my Tamron 70-200mm without any controls just for the extra reach. I know that Nikon's TC's are only made for a couple of Nikon lenses and they might not work with the Tamron lens on my Nikon body - but would they work on the GH5? Remeber - I dont need any autofocus, vibration reduction or aperture control to work since the camera cant communicate to the lens anyway. I just would need to this a manual lens with more reach. Would that work?
A lens+TC is just a lens form the camera body perspective, so if your lens+TC work on your Nikon they will (optically and mechanically) work on your GH5. So the question is whether the Nikon TC and a Tamron lens can work together.
Few people seems to use a Nikon TC with a Tamron lens, they are mostly doing the opposite, a Tamron TC added on a Nikon lens, so if you intend to use the TC mostly with the Tamron lens, a Tamron TC would be less expensive and work just as well.