GH4 time lapse aperture issue

I use the GH4 regularly for a time lapse, but there is a problem with it. Even though I am in manual mode, there is flicker in the time lapse.

The reason this happens, is that the aperture is opening and closing with every shot, as seen in this short video I made: https://youtu.be/nIM4zgFjvLM

Apparently, the aperture of the Lumix 12-32 can't move this fast or is inaccurate. So I end up doing time lapses with aperture full open. If I do that, there is no flicker.

When I use the EF mount Sigma 17-70 with a Metabones adapter, there is almost no visible flicker.

Is there any way this aperture behavior can be disabled? Not without a firmware update I'm affraid...

'Constant preview' is on by the way, I see not reason why you would want that off at all (especially in time lapse mode). When off, obviously shutter only closes at the shot. I don't know if this would make a difference, I will try this now.

Update: I just did a test and there is no difference with 'Constant preview' on or off.

Perhaps add a shutter delay? I think there is one. Too bad about that lens giving this problem, but then it is a kit lens. I just thought maybe manual focus might make a difference?  Al

As aljudy mentioned, it's lens dependent, and can occur on any brand/mount. It's known as aperture flicker in time lapse crowds. Some lenses are more susceptible to this flicker than others. I think it's partially based on that having the aperture off by ~1/6 of a stop for still photos isn't that noticeable, so most lenses are built that way. (But as you see, very noticeable in time lapse)

Canon users even have the trick to "fix" the aperture by partially unmounting the lens while in preview mode, so the contacts aren't engaged. m43 doesn't have the trick, though.

Also most lenses show more flicker at the smaller (f11 to f22) end, as being slightly bigger/smaller (the aperture blades off) by a fraction of a mm at f22 is a larger percentage than off by the same mm would be at f4. As the blades aren't moved at a lens's wide open point, you don't get aperture flicker.

See if you can find other m43 time lapse people, and what they get from different lenses. My panny 14-42 rII is pretty good at controlling aperture flicker up to at least f8, but my 100-300 isn't as clean except wide open (but usable with PP, see next PP). I haven't used my other lenses in time lapse enough yet, as I usually leave my nikon D5100 to time lapse and my GX7 for taking-photos-while-waiting-for-the-time-lapse-to-end.

You also might want to look into PP software to manage the flicker. Even free apps like GoPro's have anti-flicker features. I use LRTimelapse ($$) or VirtualDub + an anti-flicker addon (free), but there are many other options.