Flange Back issues

David Lorente · April 23rd, 2009, 01:50 PM

I bought an EX1 a year ago, so I had all the flange back problems every early users of the EX1 know.

A few weeks ago, we bought an EX3 in order to have two cameras for doing several jobs that require it. But I'm experiencing the same flange back problems that I had with the EX1.

I have tried to do the FB calibration several times, but it's not good. If I focus whit full zoom in (the classic method I have never had problems with when I worked with my old Betacam cameras), the focus point consistently goes to a greater distance when I zoom out.

Example: full zoom in (81.2mm); set the focus (the distance in the focus rings reads, say, 5 meters); zoom to 40mm, now the focus must be set to 4.5 meters; zoom to 25mm, and now the focus must be set to 4 meters to be right!

I wonder why the auto flange back procedure is so poorly designed: when I had to adjust the FB on my Betacam, I always checked that the setting was good for middle zoom settings, because if you only adjust it at wide zoom, the DOF is too great to have an accurate adjustment for the mid range focal lenghts.

I think we should ask Sony to implement one of these two things in the next FW revision:

- An auto FB adjustment program that takes readings not only in the full in and full out positions of the zoom, but also in the middle range (at 25mm, for example)
- A manual FB adjustment option: in case we are not satisfied with the automatic thing, (as I'm currently not!), maybe it would be a good point to let the user have full control of the adjustment.

Oh, and by the way, the FB fails with all the ND settings (clear, 1/8 or 1/64).

Chris Clifton · April 23rd, 2009, 02:08 PM

Contact your Sony rep immediately and demand replacement. They do not know how to fix it at Sony, so DEMAND replacement immediately. I've been down this road.

David Lorente · April 24th, 2009, 02:51 AM

I can't believe this is such a difficult thing. If the FB in this Fujinon lens has any similitude with the way it works in the classic broadcast lenses, I prefer to have a manual adjustment and set it as I want, and not as the @#¢$%& camera pretends is the right setting!

And the most funny thing is that you can clearly set the focus back to the good setting with help of the peaking indicator. I have found a workaround, which is to use the MF assist function, so the camera refines the focus to find the sharpest point. Anyway, this is NOT the way it should be.

Chris, do you think it's the whole camera that has to be replaced, or just the lens?

Anyone else is/has experienced the same issues on their EX3s?

Leonard Levy · April 29th, 2009, 09:20 PM

I have heard from a very good tech at a local rental house that this is a persistent problem with their Ex-3's and is quite serious.

Serena Steuart · April 30th, 2009, 12:25 AM

That is the subject of a thread on CML-PRO-HD, with suggestions that the camera won't hold back focus when set. So looks like a generic tech fault, but not universal with the EX3.

Mike Chandler · April 30th, 2009, 02:29 PM

Quote:

Originally Posted by David Lorente

I have tried to do the FB calibration several times, but it's not good. If I focus whit full zoom in (the classic method I have never had problems with when I worked with my old Betacam cameras), the focus point consistently goes to a greater distance when I zoom out.

I've had to do flange focus adjust quite a few times, as my lens has come off inadvertently, but once I run the test, everything is fine. Two things it might be: 1. do you have the most recent firmware, which corrects for the loss of focus when shifting from manual to auto--dont know, but maybe the fix would help. 2. I don't focus at all before running the test, just get the chart reasonably in the frame and let the test get its focus, which it will do off of almost anything, including a blank wall.

David Issko · April 30th, 2009, 05:13 PM

My Ex3 is attached to a Fujinon XS lens, so my electronic camera FB is disabled. It seems to be a point of interest in that other Sony cameras are suffering from similar issues. My V1 lost it ability to back focus and I had to send it off to be 'fixed'. Perhaps Sony are relying just a little too much on technology when such an issue is best left in manual mode, especially with the EX3 camera.

I'm sure that most here would agree to leave back focus up to the operator in a manual mode.

April 23rd, 2009, 01:50 PM	#1
David Lorente Regular Crew Join Date: Dec 2007 Location: Cuenca (Spain) Posts: 92	Flange Back issues - on the EX3! I bought an EX1 a year ago, so I had all the flange back problems every early users of the EX1 know. A few weeks ago, we bought an EX3 in order to have two cameras for doing several jobs that require it. But I'm experiencing the same flange back problems that I had with the EX1. I have tried to do the FB calibration several times, but it's not good. If I focus whit full zoom in (the classic method I have never had problems with when I worked with my old Betacam cameras), the focus point consistently goes to a greater distance when I zoom out. Example: full zoom in (81.2mm); set the focus (the distance in the focus rings reads, say, 5 meters); zoom to 40mm, now the focus must be set to 4.5 meters; zoom to 25mm, and now the focus must be set to 4 meters to be right! I wonder why the auto flange back procedure is so poorly designed: when I had to adjust the FB on my Betacam, I always checked that the setting was good for middle zoom settings, because if you only adjust it at wide zoom, the DOF is too great to have an accurate adjustment for the mid range focal lenghts. I think we should ask Sony to implement one of these two things in the next FW revision: - An auto FB adjustment program that takes readings not only in the full in and full out positions of the zoom, but also in the middle range (at 25mm, for example) - A manual FB adjustment option: in case we are not satisfied with the automatic thing, (as I'm currently not!), maybe it would be a good point to let the user have full control of the adjustment. Oh, and by the way, the FB fails with all the ND settings (clear, 1/8 or 1/64). __________________ Wire telegraph is a kind of a very, very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Radio operates exactly the same way, but there is no cat.

April 23rd, 2009, 02:08 PM	#2
Chris Clifton Regular Crew Join Date: Feb 2008 Location: Houston, Texas Posts: 56	Demand replacement Contact your Sony rep immediately and demand replacement. They do not know how to fix it at Sony, so DEMAND replacement immediately. I've been down this road.

April 24th, 2009, 02:51 AM	#3
David Lorente Regular Crew Join Date: Dec 2007 Location: Cuenca (Spain) Posts: 92	I can't believe this is such a difficult thing. If the FB in this Fujinon lens has any similitude with the way it works in the classic broadcast lenses, I prefer to have a manual adjustment and set it as I want, and not as the @#¢$%& camera pretends is the right setting! And the most funny thing is that you can clearly set the focus back to the good setting with help of the peaking indicator. I have found a workaround, which is to use the MF assist function, so the camera refines the focus to find the sharpest point. Anyway, this is NOT the way it should be. Chris, do you think it's the whole camera that has to be replaced, or just the lens? Anyone else is/has experienced the same issues on their EX3s? __________________ Wire telegraph is a kind of a very, very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Radio operates exactly the same way, but there is no cat.

April 30th, 2009, 05:13 PM	#7
David Issko Major Player Join Date: Jul 2008 Location: Melbourne, Australia Posts: 393	My Ex3 is attached to a Fujinon XS lens, so my electronic camera FB is disabled. It seems to be a point of interest in that other Sony cameras are suffering from similar issues. My V1 lost it ability to back focus and I had to send it off to be 'fixed'. Perhaps Sony are relying just a little too much on technology when such an issue is best left in manual mode, especially with the EX3 camera. I'm sure that most here would agree to leave back focus up to the operator in a manual mode. __________________ David Issko Edit 1 Video Productions

April 29th, 2009, 09:20 PM	#4
Leonard Levy Trustee Join Date: Feb 2006 Location: USA Posts: 1,684	I have heard from a very good tech at a local rental house that this is a persistent problem with their Ex-3's and is quite serious.

April 30th, 2009, 12:25 AM	#5
Serena Steuart Major Player Join Date: Jun 2006 Location: Studio Alnitak, Melbourne, Victoria, Australia Posts: 640 Images: 3	That is the subject of a thread on CML-PRO-HD, with suggestions that the camera won't hold back focus when set. So looks like a generic tech fault, but not universal with the EX3.