BIG Birger Problems -- Uncontrollable Iris

[Joe Taylor]

This is not a new problem. This mount has been sent in for repairs before with the same problem, but it has again reared its ugly head.

The problem started again yesterday when I began intermittently losing lens data. That was a concern but we forged ahead. But today and all of sudden, my lenes iris would suddenly and rapidly start stopping up and down. I am using three different Canon L Series lens' and it does this with all of them.

This has happened before when I had to send the mount in for repair. We thought we had this problem solved since it has behaved well for the past month or so but whatever the problem is, it is doing it again and at the worst possible time. Since reinstalling after getting it back for Birger, the mount has stayed on the camera with no re-installations, so I doubt I could have done anything wrong.

I am using build 20.1.6 and I am not using the Impero.

If anybody has had this happen and might know of a fix I can do in the field or back in the motel, I would love to hear from you. I can be reached by phone at 515.238.0617. We're staying in a little town called Beatty just outside of Death Valley, so there is not much for hardware stores.

Any help is much appreciated!!

[ericyoung]

Don't have a fix, but workarounds maybe:

To stop iris fluctuations you could unplug the Birger cable between iris changes.

Also if it seemed related to lens data you could try disabling S4/i in the menus, or unplugging the lens data cable inside if you have time to recollimate in the hotel.

If it gets to the point where you can't control iris at all, then maybe go back to the bad old way of setting iris on a Canon EOS body (if someone has one on set). Know it's a horrible way of working, but it would keep you shooting.

[Joe Taylor]

Hello Eric,

In the past when I was having this problem, I would have time to unplug the cable once I had my iris set, but this time, it is happening so fast that sometimes (most of the time) I am not fast enough, and even then I am no long sure I was able to unplug in time for the correct f-stop (I sometime can't tell because I have no lens data.) I could fine tune with shutter speed, but that is a pretty piss poor way to make a commercial and this producer would nix that idea the moment I might suggest.

As far as setting the f-stop on a Canon body, I could do that and have thought of it, but there is no way our producer would go for that. I could put my PL mount on, but the reason we're using my Canon lens' is because I have a 100-400 and we need that long lens for some carefully pre-planned moon rise shots tonight (a bust) and tomorrow night. My longest cine lens is a 25-250 Angenieux which is not near look when want.

I worked with this guy before at the Grand Canyon and Bryce Canyon back in September when these problems started happening and he was not pleased but he likes my work and gave me another chance. So this not only looks really bad for me, but for Birger and even Red to a unfair degree. He's a diehard film guy and is really thumbing his nose at all of this crap. I won't be sleeping tonight.

[paul engstrom]

Can you manually focus? If so--plug in the the mount...quickly set your iris and then unplug the mount. I would think you wouldn't need to ride iris very much. if that's the case you can make it through.

electronic = 1000 things that can (and do) go wrong.

:(

[Joe Taylor]

Hello Paul,

The mount/lens is racking through the iris too fast to unplug it in time to do this accurately.

[ericyoung]

I would suggest you try and phone Erik Widding direct at Birger then.

Although if I was the producer and it was a case of losing the shoot or messing around with shutters or EOS bodies, I'd do whatever it takes, no matter how piss poor a way of working it was! Just level with him, say the EOS body is the best of the solutions in an unfortunate situation, and will get the shot.

[paul engstrom]

I feel your pain Joe.

I think Eric's two suggestions are your best at this point--try and contact Erik/Birger and in the meantime use the slr set iris.

[Erik Widding]

Sounds like the mount is not making good electrical contact with the camera adapter, because your screws have loosened, and the mount is no longer sitting flat. Do the following:


Power down the camera
Loosen the four outer screws.
Loosen the four inner screws.
Make sure the mount is sitting flat.
Tighten the four inner screws (go acrosse like a car wheel).
Tighten the four outer screws (ibid).
Power the camera back up.

[Joe Taylor]

Hello Erik

On Sunday night I loosened up the mount and re-seated the mount per your instructions. After finishing re-seating I powered up and had lens data and a proper running system for about five minutes before my lens data flickered on and off and then my iris went haywire once again. Since then and for the remainder of the commercial shoot I have re-installed the PL mount and am using cine lenses until we wrap late Wednesday.