Pulling focus with the 14-140

[dresslerphoto]

We have already determined that a FF is just this side of useless with the 14-140. I have tried using spot focus (the function nob) to pull focus using auto focus. A couple inherent problems, you can't focus through an object, chain link fence for example, and when trying to set a near point, it better be something that is very easy for the camera, otherwise it will overshoot and then focus back and forth till it finds what it is looking for.

Does anyone have a solid method of pulling focus with this lens? Would appreciate any help. Thanks.

 

[Ozark]

I found it mostly imposable, hit or miss with my FF. I just ran the take a few times till i got lucky.

 

[maxusa]

I have a VariZoom lens controller, model VZPFI. It controls focus just fine. Having said that, as of this writing all known-to-me LENCs on the AF100 (the VZPFI included) have technical issues. The VZPFI issue is its calibration for aperture, which prevents the lens from opening fully in the manual mode. This means that an f/1.7 lens only opens up to f/1.9, an f/2.8 lens opens up to f/3.2, and so on. I consider this an annoyance rather than a show-stopper because, in most cases, we stop down lenses anyways and, if we need fully open in limited situations, just flip the iris switch to A (auto) or set from the camcorder. I contacted VariZoom about this glitch, but their customer support does not seem to exist... a true cost of a $120 gadget.



EDIT: The Lumix 14-140mm has a 'feature' that causes the lens to lose focus temporarily while zooming rapidly. The focus more or less recovers after you stop zooming. So this lens is probably better fit as a variable prime with variable brightness. Is there even such a term?

 

[Paul F]

The remote focus units from the various vendors will all pull focus reliably at a given focal length. Two caveats:

1. The focus pull mark on the dial will change with focal length. You probably already know that the focus point shifts with a focal length change.
2. Some dvxuser members have reported needing to use the calibrate function on their units to get the remote focus to reach infinity at certain focal lengths. Others have reported that they cannot reach proper focus at a given focal length.

A simple do-it-yourself remote focus is a 10k potentiometer. If interested, I can find the link that shows how to wire it.

 

[Lpowell]

The Lumix 14-140mm has a 'feature' that causes the lens to lose focus temporarily while zooming rapidly. The focus more or less recovers after you stop zooming. So this lens is probably better fit as a variable prime with variable brightness.

It's not a feature of the lens, it's a limitation of the camera. Panasonic and Olympus electronic lenses rely on the camera to continuously monitor and fine-tune internal iris and focus adjustments dynamically as the lens is being zoomed. If you zoom too quickly, the camera's auto-focus software may not be able to keep pace with the rate at which the lens focal length is changing. The lens may then appear to defocus and gradually regain focus as the camera catches up with the lens' zoom setting.

 

[maxusa]

It's not a feature of the lens, it's a limitation of the camera.

It sure appears as a lens feature. Two main reasons. First, when set to manual focus (camcorder does nothing), the loss of focus while rapidly zooming still occurs. Second, many well-known and regarded parfocal lenses keep focus intact when zooming. If you were correct, then any lens would struggle while zooming because, as you say, "the camera's AF software cannot keep pace." It is not happening. Well-engineered glass maintains focus on the AF100.