PXW-Z100 Auto Focus
I have recently purchased the PXW- Z100 and have found that the auto focus function is a bit touchy. Specifically when I am about 3-5 feet from a subject that I want to zoom in on. It does a very good job with close up if I manually focus, but auto focus leaves a lot to be desired. Zoomed all the way out the subject is in perfect focus. But as I zoom in it goes out of focus and waiting for it to refocus doesn't work. It just doesn't focus. I have found that switching to manual focus at that point, and then turning the focus ring or pressing the auto focus button will bring the subject into sharp focus.
So my question is if the focus is working and sees enough contrast on the subject to work when I press the focus button while in manual mode then how come it doesn't just go ahead and focus automatically when in full auto mode? I assume the center of the frame will be where the focus works best and centering the subject makes no difference for this problem. Once I have manually achieved a sharp focus while zoomed in then switching back to full automatic doesn't change the focus while still on the same subject.
I don't think there is a problem with the camera. The auto focus function does work well when I am zoomed out. And it does seem to track while I am slowly zooming in on a subject, up to a point. My other video cameras don't have this problem. As I zoom in on a subject with any of my other cameras the focus tracks with the zoom and at full zoom the subject is in perfect focus.
Is there a limitation with this camera that I'm not aware of, or is there something wrong with my technique?