Urgent: Focus issue

[Antony]

We've just started shooting on the Red One on a feature. The camera has been fine all day and then all of a sudden, the camera is out of focus. We've changed lenses. No matter what we do, it will not correct. Apart from this the camera is powering up and not showing any issues. Could the Back focus have been knocked out?

I would be grateful for any ideas on this asap.

Antony

[Douglas Underdahl]

So, you are turning the focus ring on the lens, and it won't get sharp?

What lens?

Here's a link to my videos on checking depth on the RED One (like back focus on 3 chip cameras).

http://www.youtube.com/watch?v=IhmolBMtDzg

Doug

[Antony]

Hi Doug,

It's very strange. It's been working fine all day and then all of a sudden it just drops out of focus. We tried different lenses and still the problem persisted. I cannot believe it is the sensor as the system is still working and with no errors. Surely, if there was an issue with the sensor it would generate error warnings or simply just not work.

Cheers
Antony

[jimhare]

Anthony, is the back focus ring loose? Seems like you would be able to twist it by hand based on what you are saying.

[Antony]

Hi Jim,

Many thanks for your reponse. I'm not with the camera at the moment, but I'm assured it is correct and not loose. However, until I see it myself I'll reserve my judgement.

[Colin Sheldon]

I would definitely agree it sounds like a back focus issue....

[Jeff Kilgroe]

Most likely back-focus. Even if the mount seems tight, the BF can drift. Often in extreme temperatures or large temperature shifts. If the collar isn't bolted securely enough, the BF can drift, even with normal operation of the PL mount or mounting heavy lenses.

In addition to checking the back-focus, you should also visually inspect the sensor and OLPF assembly and make sure nothing looks out of alignment or loose or damaged or dirty...

[Antony]

Many thanks Jeff/Colin. I shall investigate with your comments in mind and report back

Many thanks
Antony