12-35mm Focus Hunting Slightly on GH3 when in AFC Mode


Mu-43 Regular
Hello all. I am new to the Micro 4/3rds format, but have been shooting quite a while with Canon APS-C digitals and high quality lenses.

I recently picked up a Panasonic GH3 with the 12-35mm lens and have noticed that in AFC mode, the focus will jog in ad out slightly quickly when focusing on momentarily stationary objects. Is this normal with AFC mode? I know that continuous auto focus is an area that still needs improvement on most micro 4/3 cameras, but didn't expect this.

I would test with another lens, but this is currently the only one I have. Firmware on both body and lens are up to date, and this sounds like a different symptom than the early 12-35mm OIS jitter.





Mu-43 Veteran
This is normal behaviour for a contrast based focusing system when used with continuous autofocus, as it has to continually check the focus by focusing back and forth in tiny increments.


Mu-43 Regular
Thanks! Good to know. It was a bit disconcerting compared to the "AI Servo" mode on my Canon gear. You would figure that it would be called out in the camera's manual. I suppose this is probably more noticeable with faster glass due to the narrow depth of field.




Color Blind
Paul, welcome to Micro 4/3s. As riverr02 has mentioned, this system uses CDAF as compared to PDAF to most DSLRs like you Canon. Having said that, I have been using GH3 for about a year now, and defaults to AFC + AF-on technique, and have been happy for most of the times. Just be aware of the limitations of contrast detect AF, and you're good to go I guess.