GH4 focus hunting during zooming in manual mode

[tie]

Hi, i am new to the GH4 world (i own canon dlsrs like 5D3, 600D for many years).

My style of shooting includes using zoom during shooting, so when i first tried zooming in MANUAL mode (no AF functions enabled) with Panasonic Lumix G X Vario 12-35mm f/2.8 i was quite dissapointed how it behaves.

 

I set focus on the purple flower at 35mm, then slowly and then faster zoomed out and in (no AF or focusing by my hand). There is something like "focus hunting" during zooming. For my eyes it is very distracting, because i am used to fluent continuous loosing focus on Canon DSLR (when i am zooming). 

 

So my question is. It is normal behaviour on m43 cameras with AF lenses?

 

When i used Canon 24-105mm L with passive adapter on GH4, there is everything alright (same behaviour as on Canon DSLR body).

 

Please watch this youtube test video to see what is going on:

[andrgl]

Same problem with my 14-45mm f3.5-5.6.

[nahua]

It's well documented that zooming while shooting with the 12-35mm X lens changes aperture and focus.  Also the lens is not parafocal at all.  If you want a parafocal lens, then the Sigma 18-35mm F1.8 is the one to get.  And I have the Canon 24-105 F4L and it isn't parafocal either.

 

BTW that Lumix 14-45 kit lens is crap.  I had it and sold it.  I highly recommend the Sigma, or one of the Panasonic PZ lenses (Power Zoom) if you want to zoom in and out while recording video.

[andrgl]

If you want a parafocal lens, then the Sigma 18-35mm F1.8 is the one to get.

And it doesn't breath!