Blackmagic Forum

Hello people, I have a problem with the IRIS control to my Sigma 18-35 and Sigma 50-100. Sometimes my Ursa Mini 4.6k loses control to the iris. I have no idea why.. Ursa mini and the lenses have the latest firmware. Has anyone an idea why that could be? Thanks..!

If memory serves me right, there was a problem with older Sigma 18-35 lenses, which got solved by a firmware update FOR THE LENS (not the camera). For updating Sigma lenses you need a dock from Sigma.

I have the UM46k with firmware 4.2 and a Sigma 18-35 (bought in late 2016). No problems with the iris control so far.

Yep, found the lens firmware problem here:
viewtopic.php?f=2&t=50972&start=100#p294704

Thanks for your reply. Already checked the firmware of the lenses. So, this can't be the issue..

Anyone else has an idea?

I have this same problem and would love a solution. Lens firmware is also up to date for me. In addition to losing iris control, the iris occasionally "jumps" causing a split second burst in exposure which ruins a shot. That is the greatest concern.

Maybe it's something to do with how the mount is connecting to the lens.

I know that if I don't have my micro mounted bmpcc speed booster locked down to the cage I can sometimes cause the connection to wiggle and I assume this grinds the pins back n forth. This causes the lens to freak out, change Iris back and forth quickly or stops responding at all. If it happens I need to power down the camera and as such the speed booster down then back on and it's fine. I've yet to have it happen if the booster is bolted down to the support foot. The speed booster sits quite tightly when mounted. Lens to booster has a small wiggle but I haven't managed to force this to happen when the booster is bolted.

This only happened when using the old nifty fifty Canon lens with it's poor plastic ef mount.

Jesse Widener wrote:I have this same problem and would love a solution. Lens firmware is also up to date for me. In addition to losing iris control, the iris occasionally "jumps" causing a split second burst in exposure which ruins a shot. That is the greatest concern.

Hi all, just wondering if anyone ever got a solution to this? Having the exact same issue. Such and awesome lens but just doesnt want to work on my UM46

Thanks

Dan, as previously mentioned in your other posts about this, you need to update the lens FW, this should fix the issue.
Cheers

Hi guys,

I have encountered the same problem (no iris control/jumps) with my two Canon photo lenses:
EF 50mm f1.2 L & EF 70-200mm f2.8 II
Firmware on the UM4.6K is v4.8

Even if I use Xeen cine lenses (with no electronics inside), the camera shows randomly a f-stop number on the screen!! How is this possible?

Are there any firmware updates available for the canon lenses?

cheers, Ben

If you are having these lens issues then you should check your mount.
Are the pins damaged at all?

Those Sigma and Canon lenses are definitely supported on URSA Mini and Mini Pro software and have been for a long time.

Tim Schumann wrote:If you are having these lens issues then you should check your mount.
Are the pins damaged at all?

Those Sigma and Canon lenses are definitely supported on URSA Mini and Mini Pro software and have been for a long time.

Hi Tim, the pins seem to be fine....