Sony confirms backfocus problem

Gerald Loidl · March 29th, 2008, 12:41 PM

Paul,
yes I only had a white wall in the frame - nothing else.
I think you also could go a little closer - but thats only speculation...

cu,
Gerald

Paul Burgess · March 29th, 2008, 01:03 PM

Thanks for all the info.

I have today made up a large piece of plywood with 12 A4 BF charts on it and intend to follow your process tomorrow by placing the plywood against a vertical wall outside. I will post the results.

Holger Neuhaeuser · March 29th, 2008, 02:34 PM

Hi, I am trying all day now to reproduce your recipe, and I really doubt, that the camera stores backfocus settings for each position of the nd filter switch.

I came up with results that seemed to proove this but, when I had a chance to check real far away infinity focus, I always saw differences.

I think your method is very good to help the fb autoadjust to do its job as good as possible.
But I´m pretty shure, that it just remembers the last run, no mather if it is that with or without nd filter.

After a day of fumbling around I came up with a setup that has only slight focusloss in the nd settings and is perfect without nd filter.
I think I´ll keep that and use external nd filters as often as possible.
Thats for an earlier firmware (1.02).

Is anybody absolutely shure that other firmware versions store the backfocus settings for each nd filter setting?

I was, as long as my far focus reference was at about 20 meters distance. But as I rechecked that settings with 100 meter away objects I had to admit, that in fact it was not on the spot.

Regards
Holger

Michael Mann · March 29th, 2008, 02:52 PM

Quote:

Originally Posted by Holger Neuhaeuser

Is anybody absolutely shure that other firmware versions store the backfocus settings for each nd filter setting?

Holger, we should simply ask a Sony technician about that.

Gerald Loidl · March 29th, 2008, 03:04 PM

Quote:

Originally Posted by Holger Neuhaeuser

Hi, I am trying all day now to reproduce your recipe, and I really doubt, that the camera stores backfocus settings for each position of the nd filter switch.

I came up with results that seemed to proove this but, when I had a chance to check real far away infinity focus, I always saw differences.

I think your method is very good to help the fb autoadjust to do its job as good as possible.
But I´m pretty shure, that it just remembers the last run, no mather if it is that with or without nd filter.

After a day of fumbling around I came up with a setup that has only slight focusloss in the nd settings and is perfect without nd filter.
I think I´ll keep that and use external nd filters as often as possible.
Thats for an earlier firmware (1.02).

Is anybody absolutely shure that other firmware versions store the backfocus settings for each nd filter setting?

I was, as long as my far focus reference was at about 20 meters distance. But as I rechecked that settings with 100 meter away objects I had to admit, that in fact it was not on the spot.

Regards
Holger

Holger,
I´ve tried it with cameras with a later firmware version - FW 1.03 and FW 1.05 and it worked. I´ve tried it with objects that were about 600m away...
It works perfectly now as you can see on the pictures I posted and I switched between ND filters very often.

Michael H. Stevens · March 29th, 2008, 04:07 PM

Quote:

Originally Posted by Leonard Levy

Sony has confirmed that the backfocus problem with ND filters engaged is real and supposedly they have a fix. My camera just went in so I have my fingers crossed.

Recent cameras should already be fixed. software v1.05 is supposedly the fix. Sony repair in San Jose by the way has been very nice about dealing with this.

here is how to check it:

How to check Back Focus ( check this on a large monitor):

1. To allow for distant infinity focus, it is best to setup the camera outdoors ( this is not neccessary for a video camera but is for film or still lenses)

2. With ND filters off, zoom in ALL the way and focus on a distant object over 25 feet away (if you are indoors try it at closer distances at least 10').
KEEP YOUR APERTURE WIDE OPEN @ f1.9 THIS IS CRITICAL.
Depending on the available light, you may need to increase your shutter speed to not over expose, or perhaps even engage extra Gain as you change filter wheels.

3. Once you've focused on your distant object, zoom out full wide.
The wideangle is what we are most concerned about. That's where it will go off and you won't see it while shooting.
The wide image should still remain in focus.

4. Repeat this test with each ND setting. The camera should remain in focus regardless of the ND setting.

5. At both telephoto and full wide while keeping the aperture @ f1.9, flip through no filter then with ND filters.
The camera should remain in focus regardless of the ND setting.

Hope I explained this right its late.

Lenny Levy

How can you tell if it is in focus when you zoom out because the image is so small???

I must have this problem as a whole four days shooting is down the drain - everything out of focus!!!!

Nick Wilson · March 30th, 2008, 01:59 AM

This year's must have accessory for EX1 owners - starburst wallpaper :-)

You heard it here first!

Cheers, Nick

Brian Cassar · March 30th, 2008, 02:32 AM

Are there any more guys out there having success with this setting? I've tried it for 5 times yesterday but no such luck.

It is a 1.03 version and one of the very earliest cameras. I've scanned a Siemens star and printed it out on an A3 paper. I've printed 30 of such prints to produce a very large area! However I still could not go more than 2.5 mtrs (8 feet) away without getting something else in the screen.

And the problem in my case is also present without the ND filter. Once I'm zoomed in the picture is nice and focused - once I zoom out the picture can be seen getting soft.

I'm really eager to know whether others are having success with this recipe - as the photos attached by Gerald are really amazing and impressive.

Gerald Loidl · March 30th, 2008, 02:49 AM

Brian,
I´m very disappointed to hear that it did not work for you!
Maybe you can retry from a little further away? The testcharts did not cover the entire frame at full wide during my tests as well - that should not be the problem.
Maybe I really was just lucky - others even had success with only one test chart, which did not work for me.
Its weird...
I will retest the loaner camera with FW1.03 once again and more closely today, before it will be picked up tomorrow by UPS.
All this talk about working with only one ND-filter made me a little insecure and so I want to do some more tests. Time to open the box once again!
I will report back soon.

Brian Cassar · March 30th, 2008, 03:25 AM

Gerald, I was actually very surprised when I read your successful method because as far as I know, a back focus setting involves a mechanical change. Thus in my opinion, when one does a BF setting on ND2 I believe that one looses the BF setting of the ND off (although I might be wrong as I'm no optic technician). In fact after I've done all the steps that you had performed and seeing that it did not work for me after a number of times, I decided to do the BF setting only on the ND off setting (that is without perfoming a BF adjustment on ND1 and ND2 so as not to alter anything just in case my reasoning is correct). However on examining the footage I still saw the horrible softening of the image on going to the wide setting.

Having said this, it might be that I'm doing something wrong and I'm not suggesting that Gerald's method is wrong. It simply did not work for me.

I'm tempted to go to a professional printer to have a big blow up of a Siemens chart printed on a poster so as to have the whole frame covered from a distance of about 4 meters - I know this sounds a bit crazy - but this camera is getting me crazy in the first place. And I have a feeling that if I manage to sort out this BF issue, the issue of seeing the picture go soft when downconverting from HD to SD will be resolved - just my hunch!

Nick Wilson · March 30th, 2008, 03:35 AM

Quote:

Originally Posted by Brian Cassar

I've scanned a Siemens star and printed it out on an A3 paper. I've printed 30 of such prints to produce a very large area! However I still could not go more than 2.5 mtrs (8 feet) away without getting something else in the screen.

I guess that it is not too important that the charts cover the field of view. What is important is that there is nothing within the field of view at a different distance that will be used by the camera to get its wide angle focus. I am assuming that there is no need for proper backfocus charts - the procedure might well work if you show the camera a big expanse of brick wall or other surface sufficiently textured for it to get a focus.

Nick

Nick Wilson · March 30th, 2008, 03:41 AM

Quote:

Originally Posted by Brian Cassar

Gerald, I was actually very surprised when I read your successful method because as far as I know, a back focus setting involves a mechanical change. Thus in my opinion, when one does a BF setting on ND2 I believe that one looses the BF setting of the ND off (although I might be wrong as I'm no optic technician).

There is no mechanical adjustment. The EX1 lens is a servo controlled varifocal, which uses look-up tables to hold the focus as the lens is (mechanically) zoomed. This is cheaper than a lens optically designed to hold backfocus, and is the reason (along with electronic CAC) why the EX1 delivers the results it does at a price for the whole camera less than a 1/2 inch broadcast lens. The Auto FB process recalibrates the lookup table, which is why it is essential that the camera gets a focus at the same range at tele and wide. It seems that separate look up tables are used for each ND setting, which is why the calibration needs to be done for each ND setting.

Cheers, Nick

Gerald Loidl · March 30th, 2008, 03:51 AM

Just returned from the garden - loaded the testclips from the loaner camera (FW1.03) into Final Cut Pro and watched the clips in full resolution.
I did test shots switching between ND - filter positions multiple times.
The camera has FW 1.03 and I did the FB calibration with multiple charts on friday.
After very close inspection I can definitely say that it is perfectly fixed. The camera is tack sharp and spot on at all ND positions. Also objects really far away are sharp. (of course there are limits due to the lens glass...)
I can post another split screen image of todays testclips if you want.
Maybe you really need at least FW 1.03 to do the adjustment for all ND settings??? Does anybody know what Adam Wilt´s camera has?
So far all negative reports I read are coming from cameras with FW 1.02...

I will now put the loaner camera back into the box...

regards,
Gerald

Paul Burgess · March 30th, 2008, 04:50 AM

Thank you Gerald - I followed your instructions using a display of 12 A4 Starburst charts )my local wallpaper shop had never heard of the wallpaper) - I placed this on a piece of large plywood about 4 foot by 6 foot and placed this against a wall.

I set the camera up about 10 foot from the charts.

The wide angle shot extended onto the ground and wider than the wall - the wall was about 18 feet wide. So the wide angle view extended well outside the wall.

The result was that the softness I have previously experienced has gone.

So thanks again - it worked for me.

Holger Neuhaeuser · March 30th, 2008, 05:56 AM

Hi again,
after my dissapointing tests with the 12 focuscharts on my firmware version 1.02, I tried again.
This time I just took a huge house over the street which completly blocks the frame (about 10 metres away, relatively flat fassade) and ran fb auto with no focus charts at all.
This worked much better. But I´m very shure now that the camera remembers only the last auto allign run, at least in version 1.02.

So I took ND1 as a Medium setting and did the line up on this setting. That worked near to perfect for all settings , may be its perfect but I seem to be oversensibilized by now.

March 29th, 2008, 01:03 PM	#47
Paul Burgess New Boot Join Date: Feb 2008 Location: Brecon, Wales Posts: 23	Giving it a go Thanks for all the info. I have today made up a large piece of plywood with 12 A4 BF charts on it and intend to follow your process tomorrow by placing the plywood against a vertical wall outside. I will post the results.

March 30th, 2008, 04:50 AM	#59
Paul Burgess New Boot Join Date: Feb 2008 Location: Brecon, Wales Posts: 23	It worked! Thank you Gerald - I followed your instructions using a display of 12 A4 Starburst charts )my local wallpaper shop had never heard of the wallpaper) - I placed this on a piece of large plywood about 4 foot by 6 foot and placed this against a wall. I set the camera up about 10 foot from the charts. The wide angle shot extended onto the ground and wider than the wall - the wall was about 18 feet wide. So the wide angle view extended well outside the wall. The result was that the softness I have previously experienced has gone. So thanks again - it worked for me.

March 29th, 2008, 12:41 PM	#46
Gerald Loidl Regular Crew Join Date: Feb 2008 Location: Austria Posts: 122	Paul, yes I only had a white wall in the frame - nothing else. I think you also could go a little closer - but thats only speculation... cu, Gerald

March 29th, 2008, 02:34 PM	#48
Holger Neuhaeuser Regular Crew Join Date: Dec 2007 Location: Munich Germany Posts: 37	Hi, I am trying all day now to reproduce your recipe, and I really doubt, that the camera stores backfocus settings for each position of the nd filter switch. I came up with results that seemed to proove this but, when I had a chance to check real far away infinity focus, I always saw differences. I think your method is very good to help the fb autoadjust to do its job as good as possible. But I´m pretty shure, that it just remembers the last run, no mather if it is that with or without nd filter. After a day of fumbling around I came up with a setup that has only slight focusloss in the nd settings and is perfect without nd filter. I think I´ll keep that and use external nd filters as often as possible. Thats for an earlier firmware (1.02). Is anybody absolutely shure that other firmware versions store the backfocus settings for each nd filter setting? I was, as long as my far focus reference was at about 20 meters distance. But as I rechecked that settings with 100 meter away objects I had to admit, that in fact it was not on the spot. Regards Holger

March 30th, 2008, 01:59 AM	#52
Nick Wilson Major Player Join Date: Dec 2007 Location: Northampton, UK Posts: 259	This year's must have accessory for EX1 owners - starburst wallpaper :-) You heard it here first! Cheers, Nick

March 30th, 2008, 02:32 AM	#53
Brian Cassar Major Player Join Date: Jan 2007 Location: Malta Posts: 306	Are there any more guys out there having success with this setting? I've tried it for 5 times yesterday but no such luck. It is a 1.03 version and one of the very earliest cameras. I've scanned a Siemens star and printed it out on an A3 paper. I've printed 30 of such prints to produce a very large area! However I still could not go more than 2.5 mtrs (8 feet) away without getting something else in the screen. And the problem in my case is also present without the ND filter. Once I'm zoomed in the picture is nice and focused - once I zoom out the picture can be seen getting soft. I'm really eager to know whether others are having success with this recipe - as the photos attached by Gerald are really amazing and impressive.

March 30th, 2008, 02:49 AM	#54
Gerald Loidl Regular Crew Join Date: Feb 2008 Location: Austria Posts: 122	Brian, I´m very disappointed to hear that it did not work for you! Maybe you can retry from a little further away? The testcharts did not cover the entire frame at full wide during my tests as well - that should not be the problem. Maybe I really was just lucky - others even had success with only one test chart, which did not work for me. Its weird... I will retest the loaner camera with FW1.03 once again and more closely today, before it will be picked up tomorrow by UPS. All this talk about working with only one ND-filter made me a little insecure and so I want to do some more tests. Time to open the box once again! I will report back soon.

March 30th, 2008, 03:25 AM	#55
Brian Cassar Major Player Join Date: Jan 2007 Location: Malta Posts: 306	Gerald, I was actually very surprised when I read your successful method because as far as I know, a back focus setting involves a mechanical change. Thus in my opinion, when one does a BF setting on ND2 I believe that one looses the BF setting of the ND off (although I might be wrong as I'm no optic technician). In fact after I've done all the steps that you had performed and seeing that it did not work for me after a number of times, I decided to do the BF setting only on the ND off setting (that is without perfoming a BF adjustment on ND1 and ND2 so as not to alter anything just in case my reasoning is correct). However on examining the footage I still saw the horrible softening of the image on going to the wide setting. Having said this, it might be that I'm doing something wrong and I'm not suggesting that Gerald's method is wrong. It simply did not work for me. I'm tempted to go to a professional printer to have a big blow up of a Siemens chart printed on a poster so as to have the whole frame covered from a distance of about 4 meters - I know this sounds a bit crazy - but this camera is getting me crazy in the first place. And I have a feeling that if I manage to sort out this BF issue, the issue of seeing the picture go soft when downconverting from HD to SD will be resolved - just my hunch!

March 30th, 2008, 03:51 AM	#58
Gerald Loidl Regular Crew Join Date: Feb 2008 Location: Austria Posts: 122	Just returned from the garden - loaded the testclips from the loaner camera (FW1.03) into Final Cut Pro and watched the clips in full resolution. I did test shots switching between ND - filter positions multiple times. The camera has FW 1.03 and I did the FB calibration with multiple charts on friday. After very close inspection I can definitely say that it is perfectly fixed. The camera is tack sharp and spot on at all ND positions. Also objects really far away are sharp. (of course there are limits due to the lens glass...) I can post another split screen image of todays testclips if you want. Maybe you really need at least FW 1.03 to do the adjustment for all ND settings??? Does anybody know what Adam Wilt´s camera has? So far all negative reports I read are coming from cameras with FW 1.02... I will now put the loaner camera back into the box... regards, Gerald

March 30th, 2008, 05:56 AM	#60
Holger Neuhaeuser Regular Crew Join Date: Dec 2007 Location: Munich Germany Posts: 37	Hi again, after my dissapointing tests with the 12 focuscharts on my firmware version 1.02, I tried again. This time I just took a huge house over the street which completly blocks the frame (about 10 metres away, relatively flat fassade) and ran fb auto with no focus charts at all. This worked much better. But I´m very shure now that the camera remembers only the last auto allign run, at least in version 1.02. So I took ND1 as a Medium setting and did the line up on this setting. That worked near to perfect for all settings , may be its perfect but I seem to be oversensibilized by now.