backfocus problem at DVinfo.net

Bill Parker · February 15th, 2008, 07:31 AM

I've just discovered a focus problem - when I zoom in tight and focus and then zoom all the way out, the focus holds. If I zoom in tight again at all quickly (servo or manual), the focus is gone. It's fine if I zoom in slowly. I found a thread earlier: http://dvinfo.net/conf/showthread.php?t=111685 that talked about a backfocus procedure you could perform on the EX1's internal menus, but I couldn't find how to access them. Does anyone know how to do this?

Thanks.

Piotr Wozniacki · February 15th, 2008, 07:36 AM

Bill, what you're describing does NOT sound like a typical back-focus problem to me! Are you sure you're not in AF or MF* (manual focus assist) mode?

Anyway, here is the procedure:

1) Press and hold the "CANCEL" "SEL/SET" and "MENU" buttons simultaneously. The back focus is the bottom item in the Maintenance menu.

2) Point the camera at a back focus chart with the camera about 12' away from the chart.

3) Zoom in and focus.

4) Select "Auto FB Adjust"

5) Select "Execute"

6) The camera will zoom in and out and do an Auto Back Focus correction.

Of course, do it at your own risk. Please keep us posted!

Bill Parker · February 15th, 2008, 07:45 AM

Piotr,

Thanks. I just discovered my problem. I had MF assist on and it would lose focus after I zoomed out and went back in again. Once I disabled that, I was fine. Do you use the MF assist?

Piotr Wozniacki · February 15th, 2008, 07:56 AM

Quote:

Originally Posted by Bill Parker

Piotr,

Thanks. I just discovered my problem. I had MF assist on and it would lose focus after I zoomed out and went back in again. Once I disabled that, I was fine. Do you use the MF assist?

This is what I suspected, Bill.

No, I don't use the MF assist - I prefer to have full control myself :)

Steven Thomas · February 15th, 2008, 08:13 AM

Yes,
don't use MF assist.

February 15th, 2008, 07:31 AM	#1
Bill Parker Major Player Join Date: Jul 2002 Location: Cambridge MA Posts: 207	backfocus problem I've just discovered a focus problem - when I zoom in tight and focus and then zoom all the way out, the focus holds. If I zoom in tight again at all quickly (servo or manual), the focus is gone. It's fine if I zoom in slowly. I found a thread earlier: http://dvinfo.net/conf/showthread.php?t=111685 that talked about a backfocus procedure you could perform on the EX1's internal menus, but I couldn't find how to access them. Does anyone know how to do this? Thanks. __________________ Bill Parker www.hindsightmedia.net

February 15th, 2008, 07:36 AM	#2
Piotr Wozniacki Inner Circle Join Date: Aug 2006 Location: Poland Posts: 4,086	Bill, what you're describing does NOT sound like a typical back-focus problem to me! Are you sure you're not in AF or MF* (manual focus assist) mode? Anyway, here is the procedure: 1) Press and hold the "CANCEL" "SEL/SET" and "MENU" buttons simultaneously. The back focus is the bottom item in the Maintenance menu. 2) Point the camera at a back focus chart with the camera about 12' away from the chart. 3) Zoom in and focus. 4) Select "Auto FB Adjust" 5) Select "Execute" 6) The camera will zoom in and out and do an Auto Back Focus correction. Of course, do it at your own risk. Please keep us posted! __________________ Sony PXW-FS7 \| DaVinci Resolve Studio; Magix Vegas Pro; i7-5960X CPU; 64 GB RAM; 2x GTX 1080 8GB GPU; Decklink 4K Extreme 12G; 4x 3TB WD Black in RAID 0; 1TB M.2 NVMe cache drive

February 15th, 2008, 07:45 AM	#3
Bill Parker Major Player Join Date: Jul 2002 Location: Cambridge MA Posts: 207	Piotr, Thanks. I just discovered my problem. I had MF assist on and it would lose focus after I zoomed out and went back in again. Once I disabled that, I was fine. Do you use the MF assist? __________________ Bill Parker www.hindsightmedia.net

February 15th, 2008, 08:13 AM	#5
Steven Thomas Trustee Join Date: Sep 2005 Location: Gilbert, AZ Posts: 1,896	Yes, don't use MF assist.