MaxKitaev

Thanks guy. I'll probably stay in M-mode to at least lock aperture and shutter without pressing anything.
UGHH
We are sorry to learn that you are unable to find a certain focus mode to suit video shooting.
With reference to your enquiry regarding the various focus modes, we would like to clarify that if you shoot movies when Focus Mode is set to Single-shot AF or DMF, the Focus Mode will automatically change to (Continuous AF) and then continue to focus.

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I use mine with the rx1004 (using a Kirk to Arca QR to add weight). It balances perfectly. And it functions as it should - you can't adjust the pan speed or anything but that's not an issue if you predict movement. But my unit also has moments when it goes beserk - vibrates furiously and needs to be switched off. Hideous when it happens. Possibly caused by moving the handle off vertical too much? Unfortunately cannot be used inverted (I wanted close to ground shots).
Tim

Panning seems to do it. Worst still, when this happens it makes the footage useless. Don't get me wrong, when it's smooth, it's very smooth. But it just seems hard to get shot of more than a few seconds before it all goes to pot.

So here is the long and short of it. The Beholder DS1 is heavy. It can get some very smooth shots, but you will be challenged to keep the shot on target for more than a very short while due to the weight. Additionally, I noticed something unexpected, certain movements can cause the unit to freak out. This results in a type of fast micro-jitters, that will appear as jerky image artifacting. 
I wanted this unit to work smoothly. I do not know if this behavior is normal or if the unit is defective. But I can tell you normal handheld seems more pleasing to my eyes, despite being less smooth. Normal handheld just seems more organic. 
 

I have the old Tokina/Angineux ATX Pro 28-70 f/2.6-2.8 and its parfocal. Even though it's an AF lens, you pull the focus ring toward the camera to engage MF and it has hard stops, so pulls are repeatable. Best part - it's an amazing lens and I paid $300. It's even usable wide open, best bargain in a zoom IMO. There are a few different versions, Google the lens for a rundown on which version to look for, they pop up on eBay all the time. 

Does it have to be used on speedbooster? I'm under the strong impression that the angenieux 17-68 2.2 is parfocal and it almost covers the gh4 4k crop. With minimal cropping in post it should be roughly 50-200 FF equivalent.

I'm 99% sure that the 70-200 f/2.8 Non-IS is parfocal, i used to have one back when i shot canon. Tarantinos crash zoom often end with a very long focal length so 200mm (300mm FF equiv.) will be perfect for what you are doing.

My 24-105 definitely loses focus zooming in. I've been shooting with a 70-200 2.8 IS (not sure which model), and while it might not be completely parfocal, it does seem to retain focus pretty well when zooming in.

I don't think there are many still lenses that are really parfocal but some are better than others. Still lens mounts are not accurate enough for them to be anyway. In order for a lens to be parfocal the flange focal distance must be correct and the lens needs to be designed to do so. The reason why some say the canon lens is and some say it isn't is due to the in-accuracy of the lens mount. Basically some are closer to the correct distance than others so results vary. The speed booster is actually a positive because it can be used to adjust the back focus of the lens. If you adjust the booster until infinity hits its mark then you will have better results than you might otherwise. You may find that the canon lens is parfocal enough if you do that. No guarentees I have never tried it.
 
I don't recall which but some of the rumored parfocal canon zooms are only parfocal when zooming tele to wide.

Yep just downscale in whatever app you use. The whole 4K to HD 10bit theory was incorrect so you will gain nothing by tracking down the specialty apps that were made for this.