Problem with Autofocus using Lumix 14-140mm Lens at DVinfo.net

Rob Brookler · February 20th, 2013, 06:02 PM

Just acquired a used AF100 and Lumix G Vario 14-140 Lens. I'm getting a strange back-and-forth "shuddering/warping" in my video frame when there's any movement in the shot and the camera is set to Auto Focus. It's as though the camera is shaking or vibrating slightly (which it isn't, being that it's on a tripod). The problem disappears as soon as I switch to Manual Focus. (Also tried OIS on and off, with no effect on the problem.)

Here's a link to a brief video sample: wobble sample - YouTube

I'd appreciate any insights into this?

Daniel Epstein · February 21st, 2013, 09:22 AM

Looks like lens breathing when focus changes changing the size of the frame at different focal lengths in time to your movements.

Rob Brookler · February 21st, 2013, 11:23 AM

Thanks Daniel. Is this "lens breathing" normal for Auto Focus ... or is it a problem with the camera or lens? If it's normal, is there any camera setting that would minimize this effect?

Daniel Epstein · February 23rd, 2013, 10:46 AM

Lens Breathing is typically more noticeable on zoom lenses when changing focus. It can also be seen on prime lenses that are not designed to minimize it. If you want to see it using manual focus you should change the focus back and forth like Auto focus might do as in your sample. You should see the frame size change. This is why video lenses aren't as good for rack focus shots if you mind the size change. Cine style lenses often are designed to avoid or minimize this.

February 20th, 2013, 06:02 PM	#1
Rob Brookler New Boot Join Date: Aug 2012 Location: Los Angeles, California Posts: 5	Problem with Autofocus using Lumix 14-140mm Lens Just acquired a used AF100 and Lumix G Vario 14-140 Lens. I'm getting a strange back-and-forth "shuddering/warping" in my video frame when there's any movement in the shot and the camera is set to Auto Focus. It's as though the camera is shaking or vibrating slightly (which it isn't, being that it's on a tripod). The problem disappears as soon as I switch to Manual Focus. (Also tried OIS on and off, with no effect on the problem.) Here's a link to a brief video sample: wobble sample - YouTube I'd appreciate any insights into this?

February 21st, 2013, 09:22 AM	#2
Daniel Epstein Trustee Join Date: Jan 2006 Location: New York, NY Posts: 1,267	Re: Problem with Autofocus using Lumix 14-140mm Lens Looks like lens breathing when focus changes changing the size of the frame at different focal lengths in time to your movements.

February 21st, 2013, 11:23 AM	#3
Rob Brookler New Boot Join Date: Aug 2012 Location: Los Angeles, California Posts: 5	Re: Problem with Autofocus using Lumix 14-140mm Lens Thanks Daniel. Is this "lens breathing" normal for Auto Focus ... or is it a problem with the camera or lens? If it's normal, is there any camera setting that would minimize this effect?

February 23rd, 2013, 10:46 AM	#4
Daniel Epstein Trustee Join Date: Jan 2006 Location: New York, NY Posts: 1,267	Re: Problem with Autofocus using Lumix 14-140mm Lens Lens Breathing is typically more noticeable on zoom lenses when changing focus. It can also be seen on prime lenses that are not designed to minimize it. If you want to see it using manual focus you should change the focus back and forth like Auto focus might do as in your sample. You should see the frame size change. This is why video lenses aren't as good for rack focus shots if you mind the size change. Cine style lenses often are designed to avoid or minimize this.