Blackmagic Forum

After the 4.5 camera update to my UMP4.6k the b4 lens auto iris function no longer works. Auto exposure forces the lense to an F1.8 every time no matter if its in 1x or 2x extender. It also has an issue when powering. The lens is forced to a F18 even when the lens is in MANUEL at the zoom module. Anyone else using B4 lenses expierencing something similar?

Yes, I've noticed that, too. As a point of reference, this is the lens I'm using: Fujinon XA20sx8.5BERM-K3

Im also using a Fujinon Fujinon HA18X7.6BERM M48 Lens.

Did you ever get a successful outcome to this problem?
I have recently fitted a B4 lens mount to my URSA Mini PL 4.6K. The Fujinon Argus II A8.5x5.5 BERM-28C is one of those SD lenses that were made to such a high standard that Fuji re-branded them as HD lenses. Incredibly good bargain if you can find one.
I am using version 4.8 camera update, and if I have auto iris selected on the lens it opens up to F1.7 and stays there. This also happens if momentary push auto iris is activated. I was astonished to find that if auto iris is selected on the camera, with either manual or auto on lens, it works but only to a maximum of F10. If I want the lens to open up more I can do it manually. I would be pleased if I could find a way to auto iris to a maximum of F1.7, do you or anybody know of a way to do this?

I'm having also a problem with my B4 Canon HJ11 lens. Auto-iris function is disabled on body and viewfinder, and when I press and hold the auto-iris function on the lens the led display tells me the iris is at 1.9 but the iris goes to 16. When I release the button the iris stays at 16 and the led display tells me now the iris is 16.

Found it! It looks like a little bug. You MUST set the auto-iris slider to "Auto" on a B4 lens, then the iris menu on the lcd-screen is enabled, otherwise it's disabled. Then you have to click on the iris menu on the lcd-screen and then you also MUST set the button on the right down corner to "Auto". After that you MUST set the auto-iris slider to "Manual" on the B4 lens. Now the auto-push-iris button on a B4 lens works just fine. BUT when you power down the camera you have to do everything described above again....

That is how it works, and has been for the last year, not a bug, at least this is how the Ursa Broadcast camera B4 lens iris setting work.
Cheers

Denny Smith wrote:That is how it works, and has been for the last year, not a bug, at least this is how the Ursa Broadcast camera B4 lens iris setting work.
Cheers

It's not the Broadcast but the Ursa Mini Pro and this workflow is far from 'normal' or user friendly and also not mentioned in the user manual. Even my reseller didn't know this.

You know, you are running two posts with the same info? I am just saying this is not a FW bug, but is how BMD as the camera setup.

Yes, I understand you have the UM Pro, but the camera firmware for controlling the B4 lens iris functions is the same as the Ursa Broadcast, since the share the same camera OS, with some differences, of course. Not saying this is an industry standard, or normal for other cameras, but is just how BMD has setup its cameras to work with the B4 mount and ENG zoom lens protocols on the UM Pro and Broadcast camera.

This camera has several lens mounts, all with different iris control setups, so a single menu system needs to adapt to all the different situations. Yes, setting the auto iris for B4 lenses is a little awkward, but it works.
Cheers