Accidently Adjusted Flange Focal Length

Vincent Oliver · May 23rd, 2009, 01:23 AM

They do look a lot better, and such a tidy porch too :-)

I recently shot some video with a Pro Panasonic HD camera (expensive one) and the results looked very good, then when I shot some footage indoors using a wider aperture the same camera produced out of focus clips. The point I am making is that in most cases the depth of field will be sufficient to cover up any small errors in backfocus - even with an extreme error the Panasonic produced acceptable results (outdoors).

Glad you are happy with the results now. Tell your brother to get a grip on his room.

Chris Clifton · May 23rd, 2009, 07:25 AM

I have had back focus issues with my EX3 since I bought it almost 9 months ago, and Sony service could not fix it. And has not replaced it. I need to know if others out there are continuing to have the same issue. And if you are CLEAR about what back focus is and how to calibrate it to know if it is working. My camera loses focus, even during and after the Flange Back test, mid way through zoom. It's clean zoomed all the way in and all the way out, but inbetween, it's soft. And unusable. I need to know if others out there still have the same issue. Please check. A correctly back focused lens has NO focus issues throughout the zoom, with a proper aperture. My EX1's do not have this issue.

Mike Chandler · May 23rd, 2009, 08:27 AM

If you are doing the flange focus test properly and if you have the latest firmware which fixed the focus loss issue on the ex3's (1..03 & higher), then I'd say you have a bum camera/lens and Sony shd replace.

Glynn Morgan · August 11th, 2009, 04:25 AM

Happening again, i think it is because i'm using such a small chart. Maybe if i moved the camera closer than 3m, the book says 3m though. Is that ok?

See I zoomed out of a sharp focus and it went soft, I was able to make it sharp again by adjusting the focus when zoomed out... Should it really be this hard to get a sharp focus? I have firmware version 1.3

Vincent Oliver · August 11th, 2009, 05:10 AM

If you take your lens off, or use the camera in a dramatic change of temperature then you should perform the lens adjustment again.

Also what aperture are you using?

smaller f stops than f8 can lead to soft focus, although the depth of field will be greater.

Glynn Morgan · August 11th, 2009, 05:38 AM

I haven't yet taken the lens off, but it does get pretty cold up here. I was using f1.9 aperture

Mike Chandler · August 11th, 2009, 07:09 AM

Your iris should be on auto, Glynn. Don't think you should be having this much of a problem. In the field I've focused with no chart off a blank wall.

Glynn Morgan · August 11th, 2009, 10:04 AM

I don't know if im expecting too much off the back focus, wether acceptable is not acceptable for someone like me. :/

Vincent Oliver · August 11th, 2009, 10:17 AM

If it is out of focus then that should be unacceptable for anyone, including you Glynn

Vincent Oliver · August 11th, 2009, 10:25 AM

Are you focusing with the lens zoomed out - i.e. wide, or with it zoomed in (telephoto).?

I presume from reading your post's you are focusing at telephoto and then zooming out

Does this happen every time or only occasionally?

Are you using a manual zoom or servo zoom?

Do you have a UV filter on your lens, if yes then have you tried to zoom in and out with the filter off.

Glynn Morgan · August 11th, 2009, 08:54 PM

I use manual zoom and I have a UV filter on the camera. I didn't realise it could effect it.

Vincent Oliver · August 12th, 2009, 12:23 AM

My first stop would be to repeat the test without the UV filter.

When manually zooming are you using the lever or turning the ring, make sure you are not catching the focus ring at any stage. It looks like your focus is only out by a small amount.

The other thing you may want to check out is the diopter setting on your eye piece. Make sure that you focus your eyes on the various symbols and viewfinder information. Your subject matter will be on the same plane of focus.

When I first started photography, I did a test by focusing on a subject, take a picture, then reset the focus to infinity and focused up again. I would do this at least six times. You would be surprised at how much focus variation between shots could be seen. After a bit of practice I managed to achieve a higher success rate.

Glynn Morgan · August 12th, 2009, 03:46 AM

Thanks for the tips, I pretty much tested it every way possible, as per your suggestions. The problem was almost solved by doing the back focus adjustment closer than the recomended 3 meters. However middle distance focal lengths became soft, when I did that.

Everything usually looks OK through the viewfinder, but I know it is soft because the peaking shows I can go sharper. Screen grabs from XDCAM clip browser also show that it is soft and can get sharper (see above). I will take it into a service centre this week, I just hope they can help me. Maybe I should ask for a firmware upgrade - does that cost anything?

Vincent Oliver · August 12th, 2009, 04:12 AM

Probably taking the camera to a service centre will be your best option. Sorry I couldn't resolve it for you.

Good luck with it Glynn

Glynn Morgan · August 12th, 2009, 05:42 AM

Hey that's cool, your suggestions were good variables to eliminate.

Appreciate the help!

May 23rd, 2009, 01:23 AM	#16
Vincent Oliver Trustee Join Date: Sep 2004 Location: Chislehurst, London Posts: 1,724	They do look a lot better, and such a tidy porch too :-) I recently shot some video with a Pro Panasonic HD camera (expensive one) and the results looked very good, then when I shot some footage indoors using a wider aperture the same camera produced out of focus clips. The point I am making is that in most cases the depth of field will be sufficient to cover up any small errors in backfocus - even with an extreme error the Panasonic produced acceptable results (outdoors). Glad you are happy with the results now. Tell your brother to get a grip on his room. __________________ Eyes are a deaf man’s ears. Ears are a blind man’s eyes

May 23rd, 2009, 07:25 AM	#17
Chris Clifton Regular Crew Join Date: Feb 2008 Location: Houston, Texas Posts: 56	back focus/flange I have had back focus issues with my EX3 since I bought it almost 9 months ago, and Sony service could not fix it. And has not replaced it. I need to know if others out there are continuing to have the same issue. And if you are CLEAR about what back focus is and how to calibrate it to know if it is working. My camera loses focus, even during and after the Flange Back test, mid way through zoom. It's clean zoomed all the way in and all the way out, but inbetween, it's soft. And unusable. I need to know if others out there still have the same issue. Please check. A correctly back focused lens has NO focus issues throughout the zoom, with a proper aperture. My EX1's do not have this issue.

May 23rd, 2009, 08:27 AM	#18
Mike Chandler Major Player Join Date: May 2008 Location: Moab, UT Posts: 264	If you are doing the flange focus test properly and if you have the latest firmware which fixed the focus loss issue on the ex3's (1..03 & higher), then I'd say you have a bum camera/lens and Sony shd replace. __________________ www.packcreekproductions.com EX3, Mac Pro, FCP

August 11th, 2009, 04:25 AM	#19
Glynn Morgan Regular Crew Join Date: Feb 2009 Location: Australia Posts: 119	damn you soft focus Happening again, i think it is because i'm using such a small chart. Maybe if i moved the camera closer than 3m, the book says 3m though. Is that ok? See I zoomed out of a sharp focus and it went soft, I was able to make it sharp again by adjusting the focus when zoomed out... Should it really be this hard to get a sharp focus? I have firmware version 1.3 Attached Thumbnails Last edited by Glynn Morgan; August 11th, 2009 at 05:01 AM.

August 11th, 2009, 05:10 AM	#20
Vincent Oliver Trustee Join Date: Sep 2004 Location: Chislehurst, London Posts: 1,724	If you take your lens off, or use the camera in a dramatic change of temperature then you should perform the lens adjustment again. Also what aperture are you using? smaller f stops than f8 can lead to soft focus, although the depth of field will be greater. __________________ Eyes are a deaf man’s ears. Ears are a blind man’s eyes

August 11th, 2009, 05:38 AM	#21
Glynn Morgan Regular Crew Join Date: Feb 2009 Location: Australia Posts: 119	I haven't yet taken the lens off, but it does get pretty cold up here. I was using f1.9 aperture

August 11th, 2009, 07:09 AM	#22
Mike Chandler Major Player Join Date: May 2008 Location: Moab, UT Posts: 264	Your iris should be on auto, Glynn. Don't think you should be having this much of a problem. In the field I've focused with no chart off a blank wall. __________________ www.packcreekproductions.com EX3, Mac Pro, FCP

August 11th, 2009, 10:04 AM	#23
Glynn Morgan Regular Crew Join Date: Feb 2009 Location: Australia Posts: 119	I don't know if im expecting too much off the back focus, wether acceptable is not acceptable for someone like me. :/

August 11th, 2009, 10:17 AM	#24
Vincent Oliver Trustee Join Date: Sep 2004 Location: Chislehurst, London Posts: 1,724	If it is out of focus then that should be unacceptable for anyone, including you Glynn __________________ Eyes are a deaf man’s ears. Ears are a blind man’s eyes

August 11th, 2009, 10:25 AM	#25
Vincent Oliver Trustee Join Date: Sep 2004 Location: Chislehurst, London Posts: 1,724	Are you focusing with the lens zoomed out - i.e. wide, or with it zoomed in (telephoto).? I presume from reading your post's you are focusing at telephoto and then zooming out Does this happen every time or only occasionally? Are you using a manual zoom or servo zoom? Do you have a UV filter on your lens, if yes then have you tried to zoom in and out with the filter off. __________________ Eyes are a deaf man’s ears. Ears are a blind man’s eyes

August 11th, 2009, 08:54 PM	#26
Glynn Morgan Regular Crew Join Date: Feb 2009 Location: Australia Posts: 119	I use manual zoom and I have a UV filter on the camera. I didn't realise it could effect it.

August 12th, 2009, 12:23 AM	#27
Vincent Oliver Trustee Join Date: Sep 2004 Location: Chislehurst, London Posts: 1,724	My first stop would be to repeat the test without the UV filter. When manually zooming are you using the lever or turning the ring, make sure you are not catching the focus ring at any stage. It looks like your focus is only out by a small amount. The other thing you may want to check out is the diopter setting on your eye piece. Make sure that you focus your eyes on the various symbols and viewfinder information. Your subject matter will be on the same plane of focus. When I first started photography, I did a test by focusing on a subject, take a picture, then reset the focus to infinity and focused up again. I would do this at least six times. You would be surprised at how much focus variation between shots could be seen. After a bit of practice I managed to achieve a higher success rate. __________________ Eyes are a deaf man’s ears. Ears are a blind man’s eyes

August 12th, 2009, 03:46 AM	#28
Glynn Morgan Regular Crew Join Date: Feb 2009 Location: Australia Posts: 119	Cheers Thanks for the tips, I pretty much tested it every way possible, as per your suggestions. The problem was almost solved by doing the back focus adjustment closer than the recomended 3 meters. However middle distance focal lengths became soft, when I did that. Everything usually looks OK through the viewfinder, but I know it is soft because the peaking shows I can go sharper. Screen grabs from XDCAM clip browser also show that it is soft and can get sharper (see above). I will take it into a service centre this week, I just hope they can help me. Maybe I should ask for a firmware upgrade - does that cost anything?

August 12th, 2009, 04:12 AM	#29
Vincent Oliver Trustee Join Date: Sep 2004 Location: Chislehurst, London Posts: 1,724	Probably taking the camera to a service centre will be your best option. Sorry I couldn't resolve it for you. Good luck with it Glynn __________________ Eyes are a deaf man’s ears. Ears are a blind man’s eyes

August 12th, 2009, 05:42 AM	#30
Glynn Morgan Regular Crew Join Date: Feb 2009 Location: Australia Posts: 119	Hey that's cool, your suggestions were good variables to eliminate. Appreciate the help!