Film-Tech Forum ARCHIVE: Image size & focus fouled up with no apparent cause

This is topic Image size & focus fouled up with no apparent cause in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.

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Posted by Gracia L. Babbidge (Member # 582) on 04-13-2014, 02:21 PM:

Projector: Barco DP2K-10S Server: Doremi

We're on our third week with a feature (the Grand Budapest Hotel) that has been playing just fine, and for our first matinee today the show started with the image both too small, and well out of focus, then the tail light turned yellow. Communicator software indicated an issue with lens movement, but I don't recall the exact wording.

Nobody has screwed around with the gear, nor its settings.

First, I tried using the preset buttons to see if that rectified the image issues, and it did not. I did however hear a whining kind of sound from the direction of the lens.
[Confused]

Being that we have plenty of turnaround time between shows, I opted next to reboot the whole rig to see if that sorted it out.
Nope.
[uhoh]

I was able to use the zoom & focus buttons on the projector's keypad to get the image in focus, and sized as close to correct as could be managed - no whining from the lens as I did those adjustments, and the taillight is green again.

Anyone encountered this kind of quirk before - or do we perhaps have gremlins?

Posted by Carsten Kurz (Member # 5396) on 04-13-2014, 02:36 PM:

Focus drift or lost lens reference has been quite common on Barcos. Don't know if your specific case is typical, as it is a fairly new machine. Do you have access to the setup level on the projector/communicator? There should be a homing option in the lens setup menu. 'Lens parameters' -> 'Lens home and return'.

Try to execute it and see if it fixes the problem. It means the projector is resetting to the lens zero reference point so the presets will work again as setup initially. You will not lose your presets by performing a homing. Don't mess with your presets until you tried homing.

- Carsten

Posted by Marco Giustini (Member # 4544) on 04-13-2014, 02:47 PM:

Be aware that if the lens has not been homed and returned before the lens file were created, doing it now will cause your lens files to become inaccurate.

If you're capable of re-doing them, no problems and in fact I do agree with Carsten.

Posted by Gracia L. Babbidge (Member # 582) on 04-13-2014, 07:29 PM:

The error message: lens zoom position - target not reached

Haven't been able to locate any kind of 'lens home & return' on the communicator software.
[uhoh]

Posted by Carsten Kurz (Member # 5396) on 04-14-2014, 07:46 AM:

Search for 'home' in the current communicator manual - I assume you have that available?

- Carsten

Posted by Dave Macaulay (Member # 813) on 04-14-2014, 08:05 AM:

Sending a diagnostic package to Barco would be a good idea.
Lens home/return is in Installation/Advanced/Lens. You have to be logged in as st.
Check the right lens was installed in the software in this page: you may not be able to find the "R" number with the lens in place but the zoom ratio numbers must match the ones on the lens front ring. If it's wrong then correct it - you only need to remove the lens to get the R number if there are two otherwise identical size lenses in the "new" list, and I don't think the 10s lenses have those.
After home & return, activate a format macro (ie "Flat") and go to Configuration/Lens. Remember the "active lens file" name showing. Adjust the lens with communicator or the panel buttons - in communicator is nice because you can activate the usual test patterns directly. Once the setting is correct save it under the name you saw before (some projectors have a lot of confusing lens file names).
Repeat the whole process for any other format macros with different lens files.
Avoid setting the zoom, focus, or shift at or really close to a limit. If one is close, be sure to make the last adjustment towards the limit.
It's odd but not unknown for the projector to lose its lens settings. In my limited experience it's been because the installer didn't do a home/return when first setting it up. If a setting at or close to a limit was saved, you get the yellow light and "requested position not reached" but the screen image is pretty close to what you wanted - not grossly wrong size/focus/position.