Originally Posted by P&Struefan
It has a bigger sensor, better sensitivity and wider dynamic range, yes, but only two lenses in the entire M4/3 range have a servo zoom useable for video while the rest are manual only zooms. The Panasonic autofocus is unreliable, to put it mildly, so you would end up with a camera and a lens combo that can shoot video with better image quality but you can't power zoom and in most critical shooting circumstances, you have to rely solely on manual focus. And to have a lens combo with a comparable 20x zoom range on the G9, you are looking at at least 2 zoom lenses and the hassles that have to come with changing them in run and gun situations or in adverse conditions such as in the crowd, drizzling rain or when there is simply not enough time to change the lenses.
In actuality, as an owner of the GH5 that I’ve used extensively, the AF is not as bad as you claim, especially after firmware updates. Is it as reliable as Sony’s PDAF? No. However for many (most?) shooting situations, the simple assignment of ‘focus lock’ to one button, eliminates any concern about focus hunting. Further, focus lock is virtually instantaneous.
I’ve shot many videos using this technique, heck, I shot many videos with prior Sony cameras using the same technique and almost nobody ever commented on poor AF in my videos.
Now certainly this approach is not what you’d use for subjects moving toward or away from the camera, however it’s effective for many subjects moving laterally that aren’t in very close proximity to the camera.
My understanding is that the G9 has improved AF over the GH5. So I’m simply stating that the GH5/A9 AF, although not as good as Sony’s PDAF, is not nearly as bad as some people make it out to be. It’s best to put things in perspective.