Maintaining Focus While Zooming In/Out

[dmchord]

I'm running into some trouble maintaining focus on my HVX205A while zooming in or out. For instance, I wanted to do a slow zoom in to the front of a house. I zoomed all the way in and set focus (which is what Barry's book recommends), but when I zoomed out again I lost focus.

Auto focus for this same shot was a little slow on the uptake. It caught up eventually, but it didn't maintain focus throughout the zoom. Besides, somebody told me I should avoid using auto anything!

Is it just a matter of practice, one hand on the servo lever and one on the focus ring, until I get good enough to anticipate how the two work together? Any tips or suggestions would be much appreciated. Thanks!

[Spec-Comm]

If you zoom in and pull focus then zoom out and you're out of focus you may need to have collimation done to your camera. I would check with your local authorized service center to see if they can check it out.

Otherwise, if everything is ok with the camera, it would best to use a follow focus system to give you more control over the focus ring.

Sincerely,

Andrew Hoffman
Vice President
Specialized Communications Corp.
20940 Twin Springs Dr.
Smithsburg, MD 21783-1510 USA
800-359-1858 (US)
301-790-0103
Fax: 301-790-0173
andrewh@spec-comm.com
www.spec-comm.com
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[dmchord]

What do you mean, exactly, when you say "pull focus?"

Again, my understanding is that if you zoom in all the way and set focus, as you zoom out, the image will stay in focus without adjusting the focus ring. That could be a total misunderstanding on my part, and I sort of hope so, because it doesn't happen.

I know that when a subject moves closer to or further from the camera you have to pull focus, but what about when the distance is the same and only the zoom changes?

Lol, I guess the better way for me to phrase the question is to ask, is adjusting zoom the same thing as actually changing distance, as far as the camera is concerned?

Thanks!

[ashr]

No, it isn't. Distance changes only when you physically move the camera forward or backwards i.e using a dolly to move towards the subject or simply walking with the camera in hand. The effect you get is very different from that of a zoom, both visually and psychologically.

When you move the camera, your subject will go out of focus. This does not happen when the camera is stationary and you zoom.

Like Spec-Comm said, if you're going out of focus while zooming even after you zoomed in all the way and set focus on your subject, get the camera checked.