Accidently Adjusted Flange Focal Length at DVinfo.net

Glynn Morgan · March 14th, 2009, 01:41 AM

I accidentally ran the Flange Focal Length adjustment procedure on my ex3. I was hand holding the camera too, so I set the camera back to defaults, assuming this would fix the problem. I also re-loaded the lens properties.

How can I tell if I have stuffed something up? I am new to this flange thing. I normally use fixed lens cameras.

Vincent Oliver · March 14th, 2009, 01:52 AM

Just put the camea on a tripod and run the Auto FB Adjust again. You can download a test target from Free Charts. (The bottom left image)

Short of dropping your camera you can't realy mess things up

Glynn Morgan · March 14th, 2009, 02:10 AM

Cheers man - all these new features I'm learning do help to add to technological hypochondria, that I've messed something up.

Thanks for the link

Andy Tejral · March 14th, 2009, 07:45 AM

Just curious, not being a ex3 owner, is this an automatic back focus adjustment?

Vincent Oliver · March 14th, 2009, 08:43 AM

Yes, with the standard lens and I believe the Fujinon wide angle, but not with other lenses. The whole operation takes about 30 seconds.

Glynn Morgan · April 22nd, 2009, 02:53 AM

could my back focus be wrong if the fixed focus ring position doesn't have as much range as the electronic?

Nick Wilson · April 22nd, 2009, 03:15 AM

No. Switching in Macro only has an effect when the focus ring is forward, so if you have Macro selected you will find that it will focus closer in MF/AF than in Full MF.

Andy - on the EX3 the Auto FB procedure is in the user menus whilst on the EX1 it is a service menu item. There's a video at EX1 back focus demo on Vimeo showing how it is done.

Glynn Morgan · April 25th, 2009, 04:37 AM

The manual never said whether I should start zoomed in or out. Anyway, I have heard some people aren't getting optimal focus with the Auto Flange Back test. I hope mine doesn't have this issue.

Nick Wilson · April 25th, 2009, 07:45 AM

Quote:

Originally Posted by Glynn Morgan

The manual never said whether I should start zoomed in or out. Anyway, I have heard some people aren't getting optimal focus with the Auto Flange Back test. I hope mine doesn't have this issue.

It will not make any difference - the zoom servo needs to be engaged and the procedure will zoom as required. Auto Flange Back seems to work well, but you need a good flat target at about 4 metres which pretty much fills the field of view at wide (it will struggle if it latches on to a target at a different distance, such as a closer obstruction or a reflection in a window). I use the back wall of the house, and set shutter speed to give a wide aperture and minimise DOF.

Nick

Glynn Morgan · April 25th, 2009, 10:10 AM

It says 3m in the manual, so I just measured that. Cool, thanks guys!

Glynn Morgan · May 22nd, 2009, 07:54 AM

I have a suspicion my FB Adjustment didn't work well. So I decided to run the test again tonight. My younger brother's room had 3 meters to spare, so I used that - could anyone tell me if these Wide and Tight focuses look correct?

Olof Ekbergh · May 22nd, 2009, 08:10 AM

Yes I would say those are in focus. Hard to tell from stills though.

The best way to tell is to set up a SDI or component monitor and look at that.

After auto adjustment is done. Zoom all the way in and if you change focus and fuzzyness in the middle gets smaller it is not right. Same thing if you zoom out.

Look to see if the fuzzy part in the middle changes, when it is the smallest it is in focus. Check this in middle zoom and all the way out.

Vincent Oliver · May 22nd, 2009, 08:19 AM

Yes, it looks OK to me. But your room looks one hell of a mess.

Glynn Morgan · May 22nd, 2009, 09:05 AM

hahaha you should have read my post about whose room that was. Cheers guys, bit of night time paranoia after reviewing my shots for the day.

Glynn Morgan · May 23rd, 2009, 12:22 AM

I think these results are much better, it looked good on the viewfinder too.

What do you think?

March 14th, 2009, 01:41 AM	#1
Glynn Morgan Regular Crew Join Date: Feb 2009 Location: Australia Posts: 119	Accidently Adjusted Flange Focal Length I accidentally ran the Flange Focal Length adjustment procedure on my ex3. I was hand holding the camera too, so I set the camera back to defaults, assuming this would fix the problem. I also re-loaded the lens properties. How can I tell if I have stuffed something up? I am new to this flange thing. I normally use fixed lens cameras.

March 14th, 2009, 01:52 AM	#2
Vincent Oliver Trustee Join Date: Sep 2004 Location: Chislehurst, London Posts: 1,724	Just put the camea on a tripod and run the Auto FB Adjust again. You can download a test target from Free Charts. (The bottom left image) Short of dropping your camera you can't realy mess things up __________________ Eyes are a deaf man’s ears. Ears are a blind man’s eyes

March 14th, 2009, 07:45 AM	#4
Andy Tejral Major Player Join Date: Jan 2007 Location: New York City Posts: 523	Just curious, not being a ex3 owner, is this an automatic back focus adjustment? __________________ Andy Tejral Railroad Videographer

March 14th, 2009, 08:43 AM	#5
Vincent Oliver Trustee Join Date: Sep 2004 Location: Chislehurst, London Posts: 1,724	Yes, with the standard lens and I believe the Fujinon wide angle, but not with other lenses. The whole operation takes about 30 seconds. __________________ Eyes are a deaf man’s ears. Ears are a blind man’s eyes

April 25th, 2009, 04:37 AM	#8
Glynn Morgan Regular Crew Join Date: Feb 2009 Location: Australia Posts: 119	The EX3 Manual is useless. The manual never said whether I should start zoomed in or out. Anyway, I have heard some people aren't getting optimal focus with the Auto Flange Back test. I hope mine doesn't have this issue.

March 14th, 2009, 02:10 AM	#3
Glynn Morgan Regular Crew Join Date: Feb 2009 Location: Australia Posts: 119	Cheers man - all these new features I'm learning do help to add to technological hypochondria, that I've messed something up. Thanks for the link

April 22nd, 2009, 02:53 AM	#6
Glynn Morgan Regular Crew Join Date: Feb 2009 Location: Australia Posts: 119	could my back focus be wrong if the fixed focus ring position doesn't have as much range as the electronic?

April 22nd, 2009, 03:15 AM	#7
Nick Wilson Major Player Join Date: Dec 2007 Location: Northampton, UK Posts: 259	No. Switching in Macro only has an effect when the focus ring is forward, so if you have Macro selected you will find that it will focus closer in MF/AF than in Full MF. Andy - on the EX3 the Auto FB procedure is in the user menus whilst on the EX1 it is a service menu item. There's a video at EX1 back focus demo on Vimeo showing how it is done.

April 25th, 2009, 10:10 AM	#10
Glynn Morgan Regular Crew Join Date: Feb 2009 Location: Australia Posts: 119	It says 3m in the manual, so I just measured that. Cool, thanks guys!

May 22nd, 2009, 07:54 AM	#11
Glynn Morgan Regular Crew Join Date: Feb 2009 Location: Australia Posts: 119	I Re-adjusted it tonight. I have a suspicion my FB Adjustment didn't work well. So I decided to run the test again tonight. My younger brother's room had 3 meters to spare, so I used that - could anyone tell me if these Wide and Tight focuses look correct? Attached Thumbnails

May 22nd, 2009, 08:10 AM	#12
Olof Ekbergh Sponsor: Westside AV Join Date: Dec 2008 Location: Mount Washington Valley, NH, USA Posts: 1,365	Yes I would say those are in focus. Hard to tell from stills though. The best way to tell is to set up a SDI or component monitor and look at that. After auto adjustment is done. Zoom all the way in and if you change focus and fuzzyness in the middle gets smaller it is not right. Same thing if you zoom out. Look to see if the fuzzy part in the middle changes, when it is the smallest it is in focus. Check this in middle zoom and all the way out.

May 22nd, 2009, 08:19 AM	#13
Vincent Oliver Trustee Join Date: Sep 2004 Location: Chislehurst, London Posts: 1,724	Yes, it looks OK to me. But your room looks one hell of a mess. __________________ Eyes are a deaf man’s ears. Ears are a blind man’s eyes

May 22nd, 2009, 09:05 AM	#14
Glynn Morgan Regular Crew Join Date: Feb 2009 Location: Australia Posts: 119	hahaha you should have read my post about whose room that was. Cheers guys, bit of night time paranoia after reviewing my shots for the day.

May 23rd, 2009, 12:22 AM	#15
Glynn Morgan Regular Crew Join Date: Feb 2009 Location: Australia Posts: 119	Did it with a screenshot halfway zoomed I think these results are much better, it looked good on the viewfinder too. What do you think? Attached Thumbnails

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