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Shimming an Ursa Broadcast with Fujinon XA16X8A-XB8

PostPosted: Wed Jun 13, 2018 12:43 am
by Ken Grunberg
Our studio has been using Sony PMW-400s with the Fujinon XA16X8A-XB8 lens for years now. It is tricked out with a studio kit for zoom/focus. After adding an Ursa Broadcast into the mix, I decided to try the Fujinon with it (our studio kits do not work with the Canon lens we use for the Ursa). To my surprise, the Fujinon XA16X8A-XB8 does NOT have back focus adjustment and needless to say, the focus was way off when mounted on the Ursa.

Does anybody have an experience with using shims on the Broadcast? Is there detailed measurements one can find about the expected distance from sensor of the Ursa Broadcast, and what the Fujinon XA16X8A-XB8 actually wants?

Any help would be greatly appreciated. Thanks!
Ken

Re: Shimming an Ursa Broadcast with Fujinon XA16X8A-XB8

PostPosted: Wed Jun 13, 2018 5:35 am
by Denny Smith
You need to find out what the FFD is for the Sony camera, and set then Ursa Broadcast to the same FFD using a shim kit. This is a very technical adjustment best done with a collimating instrument.
I think you would be better off getting a Fujinon Zoom with a back focus adjustment.
Cheers

Re: Shimming an Ursa Broadcast with Fujinon XA16X8A-XB8

PostPosted: Thu Jul 05, 2018 6:25 am
by Balazs Kovacs
Hello,

I've had the same issue, I think it will just never work. The magnetic backfocus adjustment is not handled in none of the ursa series at all. If you want to go for an alternative (at least zoom demand will be the same) use the Fujinon XA20x8.5BERM-K3, or XA20x8.5BRM-K3, these are rather cheap but useable HD lenses, and alos a bit longer than the stock. We went this way

Re: Shimming an Ursa Broadcast with Fujinon XA16X8A-XB8

PostPosted: Thu Jul 05, 2018 8:43 am
by Xtreemtec
What Denny And Balazs say.. Find a different lens..

JVC HM850/890 also have a fujinon stock lens with electronic backfocus.. But this relies on communication between the camera and lens to succeed.
Googled your lens and yes it has the same Electronic Backfocus button as we have on the JVC kit lenses..

Image

Re: Shimming an Ursa Broadcast with Fujinon XA16X8A-XB8

PostPosted: Thu Feb 14, 2019 11:49 am
by Anatoly Smirnov
I managed to rebuild the back focus of URSA Broadkast. This should be rebuilt every time when replacing the camera. FF button