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-   -   Focus (https://www.dvinfo.net/forum/jvc-gy-hd-series-camera-systems/49830-focus.html)

Eloy Varela August 23rd, 2005 04:30 AM

Focus
 
Hello,

I would like to ask which has camera HD100 if they have observed
the same problem that has the Canon xl1:

Loss of focus when using the zoom lens.

thanks

Jiri Bakala August 23rd, 2005 07:15 AM

No. Unlike the XL1, this camera has a real broadcast style lens. However, it has a backfocus setting and one has to learn how to adjust it if it gets bumped or just as a matter of regular maintenance.

As for other controls; it won't do autofocus - focusing is only manual. It has the option of automatic iris switchable on the lens and its zoom could be also operated as manual or via a servomotor controlled by a rocker on the lens itself. Just like any other ENG/EFP lens.

David Slingerland August 23rd, 2005 07:16 AM

If noticed it a little bit...the canon manual lens "breaths" more. But its there ofcourse and I use the macro to not have it at all.

Chris Hurd August 23rd, 2005 07:19 AM

Breathing?
 
As a follow-up question, I would like to hear from HD100/101 owners about whether or not the stock Fuji 16x lens "breathes" during focusing (visually noticeable slight change in focal length when changing focus).

Eloy Varela August 23rd, 2005 07:50 AM

David,

You are full zoom, you make the focus, you put in position great
angle then you return full zoom. - you have always the focus?

thanks

David Slingerland August 23rd, 2005 08:06 AM

If you mean : what is the proper way to check your back-focus (it does not exist on the canon xl1 16x lens) on the lens of the JVC. Then here is as follows. Zoom completely in on a flange focal chart, check for complete focus and then zoom out. Open the back-focus ring and adjust for the sharpest picture. All along the zoom range the camera is now sharp and it cannot be out of focus... You can also do this check by using an object that gives off a sharp reflection. A lot of cameraman when changing lenses on location will do this.
for all you european folks I heard that the wideangle lens will cost around 8000 euro's. I guess that is the reason they also have an wideangleadapter in the extra's.

Eloy Varela August 23rd, 2005 08:41 AM

David,

It can that has expressed to me badly.

Please it does this:
1) Full zoom lens ,focus the image now.

2) Position zoom great angle.

3) Full zoom again.

The image is focused?

David Slingerland August 23rd, 2005 09:11 AM

If you mean adjusting the back focus..Yes that is the way and it should be all in focus....

Jiri Bakala August 23rd, 2005 11:43 AM

David, I don't think he is talking about back focus. He simply wants to know whether when you zoom in, focus and then zoom back out, the image is still in focus.
YES!

Once you focus the lens, it will stay in focus as long as you don't turn the focusing ring. Do yourself a favour and see if you can get to try any broadcast camera with any broadcast lens (Fujinon or Canon) - not the Canon XL1. That's how the lens on the HD100 will behave.


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