DBen

Hi!
I just have a few pointers that maybe will make your decision a little easier.
Concerning the heads:
Big difference between Manfrotto 500 and 502 Heads is Pan and Tilt variable drag control that 502 has which makes a huge difference when you need both slow and fast movements. The 500 has fixed Tlt and Pan drag, you have to try it if it works for you. It could be to loose for your gh4 and lens combination. I recommend to go somewhere and try it first. The 502 on the other hand can be adjusted to be completely loose or very stiff but still fluid. The 502 is much bigger and heavier and has controls on the oposite side, which many people hate, maybe you will hate it too, because of that I also recommend to try it first.
But in your case, I presume that you will be using a tele lens, so with that in mind I would reccomend the 502 because a small movement on the head is a big movement in the video on the tele end.
Concerning the tripod:
What you want is a small light tripod that extends a lot, and that's a problem becasue that kind of tripod needs to have a lot of stages (leg extensions) and with every additional leg extension adds to overall instability of the tripod. Also, having a lot of leg extensions is a real hassle, I mean real pain in the ars especially if you have to move quickly to another location and can't move with extended tripod.
Another thing, concerning the tripod (foto tripod legs) with many stages and a video head like 502 with Pan drag adjusted to be stiff, there will be a big problem regarding the tripod's Torsional Rigidity ( just google "Tripod Torsional Rigidity" ). When you pan the head in one side, the legs will twist in that direction and when you stop the movement and let go of the handle, the legs will twist again to return to their normal state and you will have a big backlash in your video. Just something you have to bear in mind. I have seen several times people blaiming video heads for the backlash, but actually the legs were to blame. Professional video tripod with a center or a floor spreader minimises that backlash.
Also if you are going to buy that small photo tripod to mount a video head on it, I recommend adding a ball adapter (half bowl) because adjusting for the horizon with the legs only is a huge hassle and time consuming. There are several on the market, cheaper ones like sunwayfoto dhy-66i (new revision) are quite good. ( http://foto-tip.pl/en/sunwayfoto-dyh-66i-leveling-base.html )
A light, small, good quality and afordable price tripod is very hard to find, though I have recently bought a Triopo foto legs tripod for 85€ and quality is very good so try to see if something from their range suite you like: Triopo GE-3232X8C ( http://foto-tip.pl/en/statyw-triopo-ge-3232x8c.html ) this is just an example, you can browse to see what other tripods they have, and maybe in your case, depends where you are from, you can probably find them cheaper somewhere else. Triopo is ok for the price, 24 months waranty in the EU and many web shops have it.
I would also recommend max 3 stages for a video tripod legs, but you need it to bee quite small when not in use and quite long when extended, and that complicates things.
Hope this helps a bit.
Cheers

Hi!
I just have a few pointers that maybe will make your decision a little easier.
Concerning the heads:
Big difference between Manfrotto 500 and 502 Heads is Pan and Tilt variable drag control that 502 has which makes a huge difference when you need both slow and fast movements. The 500 has fixed Tlt and Pan drag, you have to try it if it works for you. It could be to loose for your gh4 and lens combination. I recommend to go somewhere and try it first. The 502 on the other hand can be adjusted to be completely loose or very stiff but still fluid. The 502 is much bigger and heavier and has controls on the oposite side, which many people hate, maybe you will hate it too, because of that I also recommend to try it first.
But in your case, I presume that you will be using a tele lens, so with that in mind I would reccomend the 502 because a small movement on the head is a big movement in the video on the tele end.
Concerning the tripod:
What you want is a small light tripod that extends a lot, and that's a problem becasue that kind of tripod needs to have a lot of stages (leg extensions) and with every additional leg extension adds to overall instability of the tripod. Also, having a lot of leg extensions is a real hassle, I mean real pain in the ars especially if you have to move quickly to another location and can't move with extended tripod.
Another thing, concerning the tripod (foto tripod legs) with many stages and a video head like 502 with Pan drag adjusted to be stiff, there will be a big problem regarding the tripod's Torsional Rigidity ( just google "Tripod Torsional Rigidity" ). When you pan the head in one side, the legs will twist in that direction and when you stop the movement and let go of the handle, the legs will twist again to return to their normal state and you will have a big backlash in your video. Just something you have to bear in mind. I have seen several times people blaiming video heads for the backlash, but actually the legs were to blame. Professional video tripod with a center or a floor spreader minimises that backlash.
Also if you are going to buy that small photo tripod to mount a video head on it, I recommend adding a ball adapter (half bowl) because adjusting for the horizon with the legs only is a huge hassle and time consuming. There are several on the market, cheaper ones like sunwayfoto dhy-66i (new revision) are quite good. ( http://foto-tip.pl/en/sunwayfoto-dyh-66i-leveling-base.html )
A light, small, good quality and afordable price tripod is very hard to find, though I have recently bought a Triopo foto legs tripod for 85€ and quality is very good so try to see if something from their range suite you like: Triopo GE-3232X8C ( http://foto-tip.pl/en/statyw-triopo-ge-3232x8c.html ) this is just an example, you can browse to see what other tripods they have, and maybe in your case, depends where you are from, you can probably find them cheaper somewhere else. Triopo is ok for the price, 24 months waranty in the EU and many web shops have it.
I would also recommend max 3 stages for a video tripod legs, but you need it to bee quite small when not in use and quite long when extended, and that complicates things.
Hope this helps a bit.
Cheers

​These adapters should work, and they both control the aperture of the Nikon G type lenses.
You cannot go wrong with Novoflex, made in Germany with very high precision, very high quality materials.
Fotodiox should be ok, if you can buy it and try it with the option of returning it then why not.
But my experience with various low cost adapers is not so good, the problem is with the lenses not reaching infinity or going past infinity, they are usualy too thick or too thin (fraction of a milimeter counts here) and in my experience wide focal lenght lenses require even more high quality precise adapters.