Best Focusing From 4 Feet to 20 Feet

ENIGMACODE

ENIGMACODE

Active member
Hi Gang

I'm a 62 year old WWII documentary filmmaker. Been using #2 DVX100B's since I started on the project 5 years ago.

Anyway, I'm putting together a 20' Jib shot looking to start from about 4' from a subject, then pull up to about 20'. I'm using a pair of inexpensive 7" Delvcam Monitors. The hand held remote will start the record function, but wondering about Focus on the Jib camera?

Should I set the focus on Infinity? I don't think autofocus is a good choice. I usually use Manual Focus for interviews and action shots, but not this for this shot.

Any ideas?

Thank you :)

Here's a 3 minute trailer
http://vimeo.com/7340608
 
Actually I tried a few tests and discovered perhaps the 'Auto Focus' might work providing I'm focused (within the camera's capability) at the closet subject, (about 4 feet), and when the camera/jib pulls up the actors are within a few feet within each other not moving around too much.

*Other folks have posted cautions that the DVX100B's Remote does NOT include 'Remote Focus'

Mike
 
The DVX100B does indeed include a remote focus port. You have to use a remote that supports it; the DVX100B has two remote jacks. One for focus/iris, and the other for zoom and start-stop. Some remote controls only provide control over zoom/s-s, but others provide control over all the functions.

As for getting the shot in focus, a lot depends on what your zoom setting is, and what your iris is. At full wide angle, even with the iris wide open, and focused at 4 feet, you should have pretty much everything from 4' to infinity in focus.
 
Hello Barry

Nice to hear from you. I actually went through your book today. Very nicely done.

"You have to use a remote that supports it" Obviously you're referring to a 3rd party remote of some type. As I mentioned I have two complete camera outfits, (I'm the original owner), and the remote that came with the camera doesn't have that feature.

"even with the iris wide open, and focused at 4 feet, you should have pretty much everything from 4' to infinity in focus. " Note that I'm not using any wide angle attachments, and the stock lens is at it's widest. Barry, in what type of focus mode are you referring? Manual? AF? I did some tests using Auto Focus, (with the Jib example above), and this seemed to work fine. Providing I guess the actors will not move too much.

Thank you for your fast reply...

BTW- If you'll notice, I added a tag on Vimeo directing folks to 'DVX100B' And the documentary is scheduled to be seen on many local cable networks. Is there anything else you'd like me to add with regard to Panasonic, or you, or the DVX100B?

Looking forward to hearing back from you
Mike Fraticelli
http://www.ww2survivorstories.com/
 
Yes, I'm referring to third-party remotes, such as the Varizoom. There are remotes that offer only two functions, and others that offer all four. You'd want to make sure you got a remote that offered focus.

As far as the DOF, I'm saying put it on manual focus, set the focus to four feet, and zoom to the widest zoom position (4.5mm). At that point, anything from four feet to infinity will be in sharp focus.

Best of luck with the project!
 
Barry

One more thing so that I understand; Even with physically moving the camera up 20' on the Jib, I'll still be in focus? I guess the theory is, if I focus in the tightest it will go, I'll have LESS latitude of correct focus if the subject moves? What would be the harm in using 'autofocus' in this situation described above?

Thanx
Mike
 
Mike,

The optimal set-up would be to pull focus from 4' to infinity during the jib move once the foreground subject is breaking out of frame. Usually, you're going to have some lag in the image and the focus change won't be visible for the same reason.

Auto-focus, especially in 24 frame modes on the DVX100s, is notoriously slow and "hunty". I have lens control for any Fujinon and Canon 8-pin and 12-pin set-up. I try to keep something on hand for Sony LANC and Panasonic LANC cameras as well. A third-party follow-focus is a necessity if you're doing consistent jib work. I use Bartech, though there are many new options now for somewhat less.

Here is a suitable product for your application: http://www.varizoom.com/products/controls/vzrockpzfi.html

e
 
Hi Erick

Thanx for the quick reply - yes I've seen that varizoom device - no I don't have the money, nor can I justify the expense since I don't use the larger Jib often. But let me be clear; you say I'll have no problem if I manual focus on a plant at approx. 4 foot away, then move the Jib up to a position of about 20' away? This scene will require several takes which means refocusing at the 4' subject each time. Ok will do - ok -no problem. But let me be clear; I did a few Auto Focus tests by focusing the camera at an object about 2 feet away, then moving it to an object farther away and it actually seemed to refocus fine. I realize the reaction adjustment is slow, and perhaps my test wasn't ideal because I focused from one inanimate object to another inanimate object. True?
 
What I'm saying is that you don't have to worry about focus. On a 1/3" camera like the DVX, the depth of field is very deep. If you set the camera to fully zoomed out, that's 4.5mm on the lens. At that zoom position, even with the lens fully wide open, you can have everything in razor sharp focus from 2 feet to infinity. No need to focus at all. No need for remote focus. Just set the lens to focus at four feet, and everything from 2 feet to infinity will be in sharp focus.

If you're zooming in on the lens (i.e., you're not at full wide-angle 4.5mm) then the numbers will change, but if you're zooming all the way out, then you won't have to worry about focusing at all.
 
ENIGMACODE said:
Hi Erick

Thanx for the quick reply - yes I've seen that varizoom device - no I don't have the money, nor can I justify the expense since I don't use the larger Jib often. But let me be clear; you say I'll have no problem if I manual focus on a plant at approx. 4 foot away, then move the Jib up to a position of about 20' away? This scene will require several takes which means refocusing at the 4' subject each time. Ok will do - ok -no problem. But let me be clear; I did a few Auto Focus tests by focusing the camera at an object about 2 feet away, then moving it to an object farther away and it actually seemed to refocus fine. I realize the reaction adjustment is slow, and perhaps my test wasn't ideal because I focused from one inanimate object to another inanimate object. True?
Click to expand...

I have a method for controlling Focus, Iris, Zoom and Run/Stop whenever I operate a jib. While Barry is right about the deep, forgiving nature of 1/3" imagers under lit conditions, I strive to bring the proper tools to the job. Sometimes budget can be a real impediment toward having every tool at your disposal.

You can try the auto-focus method or simply lock focus at 4' and see how it looks once you're in your #2 position.
 
You could, of course, do a test on a tripod instead of a jib.
Shoot an object 4 ft away, then pan to an object 20 ft away.
As Barry said, you'll probably find everything in focus, but it would be an easy test to do- even try focus at 6 ft, 8 ft, see if there's any noticeable difference (playing back on a good monitor).
And good luck with your project!
 
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