Sony confirms backfocus problem

Pavlos Symeon · April 1st, 2008, 08:54 AM

Well did Gerald's routine and back focus is still wrong. Actually after the two EX1s came back from service (first time) the zoom out (wide angle) setting didn't look as bad as it was before service.
Now for the bad news: Whole image be it zoomed in all the way or at widest focal length looks soft. i can't even have a pinch sharp image at telephoto. Another thing is that I can see cyan and red coloration at the edge of some of my subjects. Is that color aberration?
Got a call from SONY and they asked me to send both cameras back for the second time.
Generally it seems that backfocus is not the major issue but achieving a sharp focus in general.

Michael Mann · April 3rd, 2008, 01:18 AM

Im am going to buy an EX1 during a vacation in the US and will not have access to an external monitor, hence my question:
Is it possible to judge proper or incorrect backfocus merely on the EX1' LCD, when magnification is switched to 1:1? I will carry a focus chart with me. Thanks in advance.

Gerald Loidl · April 3rd, 2008, 04:51 AM

Michael,
you can see the backfocus problem on the LCD if you use the expanded focus.
Make sure to turn the focus to the 0,8m stop once you zoomed out, to make sure if there is any difference. Try it with objects that are far away.

regards,
Gerald

Piotr Wozniacki · April 3rd, 2008, 05:42 AM

So far, I've not witnessed the typical backfocus problem symptomps with my EX1 - i.e. regardless of the ND filter settings, when I zoom in - focussed - zoomed out to reframe, the focus still held OK.

However, sometimes I'm in doubt when after engaging ND filter with auto iris on, I'm loosing focus. I thought (and would like to still think) this is due to the change in iris opening, which changed my DOF (and with 1/2" sensors it can be more noticeable than with my previous cameras like the V1 which only has 1/4" imagers).

To make absolutely sure, please tell me again what probably has been said many times already: when testing for backfocus problem, do I zoom in and focus for infinity before zooming out? Or does the fact that I'm loosing focus when engaging/disengaging ND with auto iris on also suggest my backfocus needs adjustment? Thanks!

Gerald Loidl · April 3rd, 2008, 06:09 AM

Piotr,
It´s pretty easy to check.
Make sure that iris is set to manual and that ƒ1,9 is set. Adjust the brightness of the picture with the shutter speed.
Zoom in to an object thats very far away. Focus. Zoom out and see if your pictures is still sharp.
After you have zoomed out also turn the focus to the 0.8m stop and watch if the image gets sharper. If it does - your backfocus is off. If it gets blurry when turning the focus - its probably o.k.

When you checked your backfocus before - did you have the aperture wide open? Did it open further when you engaged auto iris?

Piotr Wozniacki · April 3rd, 2008, 06:47 AM

Quote:

Originally Posted by Gerald Loidl

When you checked your backfocus before - did you have the aperture wide open? Did it open further when you engaged auto iris?

Yep - that's the point. I never noticed striking softness when reframing, therefore I assumed my backfocus is OK. Only now, after I invested in a 50" HDTV as a preview device and watching some of my recordings again, do I notice that sometimes when engaging ND, my focus gets soft untill I compensated - but still, I think the autoiris was on and it simply opened up, thus decreasing DOF.

Nevertheless, I'm going to perform the proper checking procedure as you described, Gerald. Thanks!

Bob Hart · April 3rd, 2008, 07:01 AM

I think hopefully a qualified camera tech will chime in here and maybe make some helpful comments.

It is possible with a PD150 to blow the image all out soft and furry if an overbright image is laid on the CCD and controlled only with shutter speed.

Unless the experiment is carefully controlled, it may be possible for a self-fulfilling "false" backfocus defect to be generated in the EX1 in the search for one, genuine backfocus faults in some cameras notwithstanding.

Michael Mann · April 3rd, 2008, 07:30 AM

Gerald, can the LCD's expanded focus moved to the corners of the frame to control focus there as well?

Gerald Loidl · April 3rd, 2008, 07:32 AM

Michael,
unfortunately this is not possible - its only a center zoom.

Gerald Loidl · April 3rd, 2008, 07:37 AM

Quote:

Originally Posted by Bob Hart

I think hopefully a qualified camera tech will chime in here and maybe make some helpful comments.

It is possible with a PD150 to blow the image all out soft and furry if an overbright image is laid on the CCD and controlled only with shutter speed.

Unless the experiment is carefully controlled, it may be possible for a self-fulfilling "false" backfocus defect to be generated in the EX1 in the search for one, genuine backfocus faults in some cameras notwithstanding.

Thats not the case here... It could be done, but then it would also be blurry if fully zoomed in. With ND2 on, the image itself is rarely too bright as well. I think what you mean is that one can also create a blurry image if the aperture is almost closed at ƒ16, as the EX1´s lens sweet spot actually is below ƒ8. If you close it further, the image starts getting blurry again and is completely fuzzy short before its closed completely. (but thats perfectly normal and differs from lens to lens)
I studied camera and work as a professional cameraman for 15 years now - so believe me, I know how to check backfocus ;-)

Leonard Levy · April 3rd, 2008, 08:45 PM

The method I described at the beginning of this thread is an accurate way to test back focus as are all of Gerald's comments. Like Gerald I spent many years as a 16mm tech and worked in rental houses checking lens back focus more times than i would like to recall. its not brain surgery and its easy to tell if you are on or off, but a large monitor is essential.

Lenny Levy

Dennis Joseph · April 4th, 2008, 08:20 AM

Quote:

Originally Posted by Leonard Levy

The method I described at the beginning of this thread is an accurate way to test back focus as are all of Gerald's comments. Like Gerald I spent many years as a 16mm tech and worked in rental houses checking lens back focus more times than i would like to recall. its not brain surgery and its easy to tell if you are on or off, but a large monitor is essential.

Lenny Levy

I feel like my bf is not as sharp as I would want it but i'm pretty much done with this subject for the next 3 months. I'm not going to even worry about this for a couple of reasons.

A. there is nothing you can do to completly make it perfect that has been confirmed.

B. i'm going to wait till sony makes a press release or has some documentation about the situation and an updated firmware that specifically fixes the bf problem.

Until then, i'm going to do like Phil Bloom and focus on the things that the camera CAN do.

Steven Thomas · April 4th, 2008, 08:31 AM

Quote:

Originally Posted by Dennis Joseph

I feel like my bf is not as sharp as I would want it but i'm pretty much done with this subject for the next 3 months. I'm not going to even worry about this for a couple of reasons.

A. there is nothing you can do to completly make it perfect that has been confirmed.

B. i'm going to wait till sony makes a press release or has some documentation about the situation and an updated firmware that specifically fixes the bf problem.

Until then, i'm going to do like Phil Bloom and focus on the things that the camera CAN do.

I'm not sure how you define perfect, but it's not an issue with some cameras. Gerald was able to adjust two cameras. Mine never had the problem, and I'm as anal as they come... LOL...
Now, don't get me going about vignetting. That's another story.

You're right about kicking back and waiting for Sony to address this issue with an official statement. It's obvious they know this is an issue. There have been some that have tried a couple cameras just to find out that they all had the BF issue.

Bob Hart · April 4th, 2008, 11:07 AM

Gerald.

As usual, I probably opened my mouth a bit too soon.

I also endorse Gerald's comment. Enjoy the things the camera can do. I regret I did not have any more than my few hours to play with the demo camera here.

It did not seem to have a backfocus problem and the dealer suggested that the vignette problem had been dealt with when I mentioned it.

I did not find it in direct-to-camera use but with a Mini35 on front, the steadyshot had to be turned off otherwise it did bring in the edges of the prism path very deep into the TV safe area.

Holger Neuhaeuser · April 7th, 2008, 06:29 AM

Got my camera back from Sony. They where pretty fast from the free pickup to return it took only 5 days (weekend inbetween).
They updated the firmware to 1.05
Focus with N2 perfect.
Focus with Nd1 and Nd off slightly soft.

After doing the fd autoallign to a brickwall at about 13m away,
it keeps focus in all nd settings.

That prooves in my opinion
firmware 1.02 no go , firmware 1.05 works (can´t say anything about 1.03)
and sony has problems using their own autoallignment, but they obviously try to do their best with a fast service.
So after messing around for nearly 2 weeks with that problem, I seem to have a fixed cam now.

Thats like most electronic products nowadays:
They are like bananas, they ripen at the client.

Holger

April 3rd, 2008, 01:18 AM	#92
Michael Mann Major Player Join Date: Dec 2005 Location: Kelkheim, Germany Posts: 375	backfocus control on LCD? Im am going to buy an EX1 during a vacation in the US and will not have access to an external monitor, hence my question: Is it possible to judge proper or incorrect backfocus merely on the EX1' LCD, when magnification is switched to 1:1? I will carry a focus chart with me. Thanks in advance. __________________ Michael

April 3rd, 2008, 05:42 AM	#94
Piotr Wozniacki Inner Circle Join Date: Aug 2006 Location: Poland Posts: 4,086	So far, I've not witnessed the typical backfocus problem symptomps with my EX1 - i.e. regardless of the ND filter settings, when I zoom in - focussed - zoomed out to reframe, the focus still held OK. However, sometimes I'm in doubt when after engaging ND filter with auto iris on, I'm loosing focus. I thought (and would like to still think) this is due to the change in iris opening, which changed my DOF (and with 1/2" sensors it can be more noticeable than with my previous cameras like the V1 which only has 1/4" imagers). To make absolutely sure, please tell me again what probably has been said many times already: when testing for backfocus problem, do I zoom in and focus for infinity before zooming out? Or does the fact that I'm loosing focus when engaging/disengaging ND with auto iris on also suggest my backfocus needs adjustment? Thanks! __________________ 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

April 3rd, 2008, 07:30 AM	#98
Michael Mann Major Player Join Date: Dec 2005 Location: Kelkheim, Germany Posts: 375	Gerald, can the LCD's expanded focus moved to the corners of the frame to control focus there as well? __________________ Michael

April 1st, 2008, 08:54 AM	#91
Pavlos Symeon Regular Crew Join Date: Nov 2007 Location: Athens, Greece Posts: 48	Well did Gerald's routine and back focus is still wrong. Actually after the two EX1s came back from service (first time) the zoom out (wide angle) setting didn't look as bad as it was before service. Now for the bad news: Whole image be it zoomed in all the way or at widest focal length looks soft. i can't even have a pinch sharp image at telephoto. Another thing is that I can see cyan and red coloration at the edge of some of my subjects. Is that color aberration? Got a call from SONY and they asked me to send both cameras back for the second time. Generally it seems that backfocus is not the major issue but achieving a sharp focus in general.

April 3rd, 2008, 04:51 AM	#93
Gerald Loidl Regular Crew Join Date: Feb 2008 Location: Austria Posts: 122	Michael, you can see the backfocus problem on the LCD if you use the expanded focus. Make sure to turn the focus to the 0,8m stop once you zoomed out, to make sure if there is any difference. Try it with objects that are far away. regards, Gerald

April 3rd, 2008, 06:09 AM	#95
Gerald Loidl Regular Crew Join Date: Feb 2008 Location: Austria Posts: 122	Piotr, It´s pretty easy to check. Make sure that iris is set to manual and that ƒ1,9 is set. Adjust the brightness of the picture with the shutter speed. Zoom in to an object thats very far away. Focus. Zoom out and see if your pictures is still sharp. After you have zoomed out also turn the focus to the 0.8m stop and watch if the image gets sharper. If it does - your backfocus is off. If it gets blurry when turning the focus - its probably o.k. When you checked your backfocus before - did you have the aperture wide open? Did it open further when you engaged auto iris?

April 3rd, 2008, 07:01 AM	#97
Bob Hart Inner Circle Join Date: Dec 2003 Location: PERTH. W.A. AUSTRALIA. Posts: 4,476	I think hopefully a qualified camera tech will chime in here and maybe make some helpful comments. It is possible with a PD150 to blow the image all out soft and furry if an overbright image is laid on the CCD and controlled only with shutter speed. Unless the experiment is carefully controlled, it may be possible for a self-fulfilling "false" backfocus defect to be generated in the EX1 in the search for one, genuine backfocus faults in some cameras notwithstanding.

April 3rd, 2008, 07:32 AM	#99
Gerald Loidl Regular Crew Join Date: Feb 2008 Location: Austria Posts: 122	Michael, unfortunately this is not possible - its only a center zoom.

April 3rd, 2008, 08:45 PM	#101
Leonard Levy Trustee Join Date: Feb 2006 Location: USA Posts: 1,684	The method I described at the beginning of this thread is an accurate way to test back focus as are all of Gerald's comments. Like Gerald I spent many years as a 16mm tech and worked in rental houses checking lens back focus more times than i would like to recall. its not brain surgery and its easy to tell if you are on or off, but a large monitor is essential. Lenny Levy

April 4th, 2008, 11:07 AM	#104
Bob Hart Inner Circle Join Date: Dec 2003 Location: PERTH. W.A. AUSTRALIA. Posts: 4,476	Gerald. As usual, I probably opened my mouth a bit too soon. I also endorse Gerald's comment. Enjoy the things the camera can do. I regret I did not have any more than my few hours to play with the demo camera here. It did not seem to have a backfocus problem and the dealer suggested that the vignette problem had been dealt with when I mentioned it. I did not find it in direct-to-camera use but with a Mini35 on front, the steadyshot had to be turned off otherwise it did bring in the edges of the prism path very deep into the TV safe area.

April 7th, 2008, 06:29 AM	#105
Holger Neuhaeuser Regular Crew Join Date: Dec 2007 Location: Munich Germany Posts: 37	Got my camera back from Sony. They where pretty fast from the free pickup to return it took only 5 days (weekend inbetween). They updated the firmware to 1.05 Focus with N2 perfect. Focus with Nd1 and Nd off slightly soft. After doing the fd autoallign to a brickwall at about 13m away, it keeps focus in all nd settings. That prooves in my opinion firmware 1.02 no go , firmware 1.05 works (can´t say anything about 1.03) and sony has problems using their own autoallignment, but they obviously try to do their best with a fast service. So after messing around for nearly 2 weeks with that problem, I seem to have a fixed cam now. Thats like most electronic products nowadays: They are like bananas, they ripen at the client. Holger