Ok,to Ex owners with back focus problems,how obvious is it if your back focus is off ?
Are you able to see it on the cam lcd or do you need a big monitor to see it ?
I think mine is ok,i've also checked it by connecting the cam to a 40 inch HD lcd.
I've posted a vimeo clip,could someone who has seen a bad back focus have a look and let me know.

Thanks. Paul
The link is below.

http://www.vimeo.com/815100

I get the vimeo message that this clip is protected and private.
Cant watch it.
On my cameras I could see it on the LCD at first. When it got better I could still see it with the expanded focus function on fullscreen on monitors.

OOps,it's public now,i just changed it and checked the link from here.

paul.

Paul,
it looks pretty soft to me - I think your backfocus is off as well.
What were your camera settings? The castle in the background and the tree in front of it definitely are getting out of focus... But as the file is pretty much compressed its a little hard to judge.

cu,
gerald

Thanks for looking at it .
So how do i fix the back focus ?
I know i need a backfocus chart but how big does it have to be and how far away from the cam ?

Thanks,Paul.

looks fine to me, paul, if you're shooting with DETAIL off.
If detail is on...that may be another story.

Hi Bill. Thanks for replying.
Yes detail was off,with standard PP. I'd only just got the cam and hadn't got to PP's at that point. I'm now using your PP with the detail on and it does look sharper than that clip.
I'll do the test again and put another clip on vimeo.
What is the absolute best way to check for back focus problems ?
Is the adjustment something that all of us will have to do at some point with this cam or are there just a few unlucky owners ?

Regarding the chart,how big does it need to be ? A4 ? And how far away ?
Where would i get a chart from,there's a few online for download ? Preston media for one ?

Thanks,Paul.

I'll refer you here.....
http://www.dvinfo.net/conf/showthread.php?t=110220

DSC Labs makes some very nice test charts, but, they're pricey. Obviously, the bigger they are, the better. I always use a star chart for focus issues.

One more note: Backfocus issues can crop up with the ND filters selected. I suggest you check with and without the use of the built in ND filter wheel.

I just found an interesting article about EX1 back focus.

http://provideocoalition.com/index.php/awilt/story/ex1_misfocusing_explained/

Interesting part about using faster shutter speeds instead of using the built in ND filters.

And i just downloaded the same back focus chart from the link below

http://www.creativevideo.co.uk/public/articles.php?article=2

Paul.

I am even more convinced now that there are two backfocus LUT's built into the EX1 - one for ND1/2 (ND on) and one for "ND Clear" (ND off).

I had a friend's camera and it had terrible backfocus when the filters were engaged, but perfect backfocus without the ND's.

We did a backfocus correction in both modes (re-doing the auto back focus with ND off and with ND 1) - and there was a marked improvement in the "ND on" backfocus and no degradation of the "ND off" backfocus.

For those having trouble with ND 1/2 backfocus, try doing the backfocus adjustment twice - once with ND 1 and once with ND off.

MM,that's contradicting what that review is saying,the focus is either correct with filter on or filter off,not both.

Paul.

Has anyone done a back focus yet and made a right mess of it,ie made it worse ?
I'm not sure if mine needs doing,it's certainly not bad.
Do i want to risk it ?

Paul.

Hi, Eric

I know how to adjust back focus the old fashioned way, but of course, that knowledge does not work w/ the EX-1.

Any chance I could get some instruction?

I apologize if this was already posted. I read through this thread rather quickly.

Jac

MM,that's contradicting what that review is saying,the focus is either correct with filter on or filter off,not both.

Paul.

Yes, that's true. But my results were different.

Someone published, a while back, some white papers together with a patent for adjusting back focus by making some of the elements in a zoom lens adjustable, not actually the rear flange, as is the conventional approach. There is some computational power needed for the adjustment algorithms to do their thing and move the adjustable elements. If you hose your system, it's only because you weren't set up properly. I have done the process 3 times, the second time it failed. But, I'm sure it was because I had too small of a target. I repeated the process, immediately, and all was well.

On the basis of optics, I don't see how the same backfocus adjustment will work with and without the ND filter. Inserting a plano-parallel piece of glass in a converging optical path WILL shift the focal point. It would make a lot of sense to me to have two memory locations for with and without the ND filter.

So Bill are you saying that the review might be completely correct and that Eric is right about 2 back focus settings ?

Paul.

Sony has acknowledged that there is a backfocus problem with earlier versions of the firmware pre 1.05. I don't know how common it is but it seems to be very common. Seems to me if its a firmware issue than it would be a universal problem.
You do need to look at it on a largermonitor. The problem is that it is different with and without ND rolled in. I just had mine repaired by Sony ( new firmware) and will get it Monday. If you have that problem it has to go in to Sony.

See this thread

http://dvinfo.net/conf/showthread.php?t=117307

This is issue is major and should probably be a recall. It should at least be a sticky on this forum. Who's in charge of that.
Lenny Levy

Paul...

I cannot, ever, say with absolute certainty. Sony doesn't communicate with me. But, it would make sense to my way of understanding, that there would be two settings stored in memory.

Read this:
http://www.patentstorm.us/patents/5600372.html

Bill,you say you 've done your back focus 3 times.
Did you do it with or without ND ?
2nd time failed because your target was to small,what size did you use and how far away ?
I've only got an A4 size chart because that's all my printer will go up to,is A4 big enough ? How far away should i place a chart this size ?
I printed it on glossy photo paper,highest quality.

Paul.

Bill,you say you 've done your back focus 3 times.
Did you do it with or without ND ?

BOTH

2nd time failed because your target was to small,what size did you use and how far away ?

12 ft (3.7 meters) on A3 paper


I've only got an A4 size chart because that's all my printer will go up to,is A4 big enough ?

I would think so

How far away should i place a chart this size ?
I printed it on glossy photo paper,highest quality.



Paul.


see answers above


By the way...IF IT AIN'T BROKE, DON'T FIX IT

Adam Wilt has a take on the ND back focus issue over on the Pro Video Coalition site.

Sorry for stating the obvious - I missed the previous page.

Ok i uploaded footage with detail on,onto Vimeo.
After watching the footage myself i have to say that Vimeo isn't giving that high a quality as far as trying to see the back focus issues.
I'm watching the same clip side by side on my pc,one clip on Vimeo,the other clip on VLC,raw MXF files, which look great so obviously don't depend on vimeo to scrutinise back focus issues.

However i have adjusted my backfocus today and i have seen an improvement on the cam and pc via VLC player,i'm uploading that footage soon so i'll post that link on here.

I'n the meantime i've posted another clip,i filmed the back focus procedure with my small cam,i was a bit nervous because i didn't know what to expect when doing the adjustment so if anyone else out there is thinking of doing theirs,they can see what happens first.

http://www.vimeo.com/819802


Paul.

I don't know if anyone has asked this question or if it makes sense but has anyone tried "peaking" when zooming out during ND 1 and ND 2?

Would it still show peaking even if it was out of focus or would it go off?

Thought this question might make more sense in this post.

it still has some peaking - even when its soft...

it still has some peaking - even when its soft...

That is interesting because I def. see peaking when I zoom out.

And what got me interested in Paul's clip is the "BLK balance" entry in the Maintenance menu. It is grayed-out; I wonder if anyone with a higher FW number has got it active?

Had some try this afternoonwith a back focus chart.
Zoom in, focus, zoom out seems to be fine without ND filter.
With ND filter, I have a small shift. The best way to track it is zooming out to 25mm. Zooming out wide you get too much depth of field to be able to see the shift, even with a true HD 24" monitor.

The shift in back focus is not a real problem, but is present.
I may wait for some months and send the camera back to sony when the new firmware is out...
Once you know you have the problem, it's not a problem anymore. I do fictions and not documentary so I never have a zoom out during a shot. The solution is to use expand focus instead of zoom in for focus pulling.