After having had the camera for a few weeks (I just recently started using it with regularity), I've come to the conclusion that my camera's factory-set backfocus is seriously out of adjustment. At first I thought it was inattention on my part, but careful testing over the last few days points to a definite problem. I use manual focus almost exclusively, so I've not tested in servo-mode.

Zoom in to an object 50 feet away, focus, zoom wide, and the entire frame is soft. In fact, I must pull focus all the way to the closeup extreme for acceptable results on wide shots. Of course this becomes less pronounced as I stop down the iris.

Via another thread, I learned how to access the maintenance menu to set backfocus. I'm familiar with doing this on a pro lense, but I'm wondering if I should attempt it with the EX, in that it works much differently and I don't own a focus chart. If I tried this, would I void the warranty, and is this even possible without using a chart?

I'll ship it back for proper service if need be, but I'd prefer not to. I've not yet ruled out user error, either. Any ideas?

Bill

Bill,

I have done this - it took all of 30 seconds and seemed to work perfectly. I just googled a back focus chart on the net and printed it out. Taped the chart on a white door and set the camera up on a tripod about 3.5meters away - followed the instructions on the thread - and it all happened automatically.

Hope this helps.

Thanks, Graeme, I'll give it a shot. Did your camera arrive needing the backfocus adjustment or were you attempting to correct the vignetting issue?

On a side note, I can't understand how Sony could ship a camera so seriously out of whack. Maybe it got jostled around on the boat.

I have also done it - very simple and not too scary process.

Back focus seems spot-on afterward.

Bill,

I hadn't used the camera enough to see any substantial back focus issues - but yes I was trying to sort out the vignetting issue. My replacement camera arrives tomorrow. I will check its back focus during the week.

Graeme, please keep us informed.

I also experienced the same simptom, and I fixed it for myself by using the information in this site. I'm quite happy now. Can't understand the QC level of Sony.

I also experienced the same simptom, and I fixed it for myself by using the information in this site. I'm quite happy now. Can't understand the QC level of Sony.


From the little I know about manual lenses it's not unusual to have to reset or at least check backfocus regularly. It may well have been correct when it left the factory. If my hunch is right it's not a fault, it's just how optics are, unless you want to spend a lot of money on exotic materials backfocus will be affected by temperature.

But unlike with manual lenses, Sony does not intend for the end user to adjust the backfocus. The backfocus adjustment is hidden in a secret maintenance menu intended for service personnel.

Even with that being the case, I intend to use adjust the backfocus in my EX1 with the almost the frequency that I would on a manual camera - especially after jarring transport.

The process is simple and arguably more foolproof on the EX1 than with manual lenses.

It's pretty impressive that Sony have created an automated, adjustable backfocus with some sort of internal motor that can be implemented from a soft menu - even if they never intended to let us use it!

Bill,

I have done this - it took all of 30 seconds and seemed to work perfectly. I just googled a back focus chart on the net and printed it out. Taped the chart on a white door and set the camera up on a tripod about 3.5meters away - followed the instructions on the thread - and it all happened automatically.

Hope this helps.

Graeme, how big a chart is required for this purpose - from 3.5m looks like an A4 card suffices?

Just a thought - would just displaying it on a 24" LCD be OK for the purpose?

Piotr,

(though I am not Graeme)

A4 or the US equivalent 8.5x11" worked for me. It also didn't seem to matter too much about other objects in the room (though I did not have anything big between the chart and camera).

I am not sure that it's the case, but it would make sense that the backfocus algorithm looks at the center of frame when zoomed wide.

I am not sure that it's the case, but it would make sense that the backfocus algorithm looks at the center of frame when zoomed wide.

Thanks Eric,
this was my question regarding the backfocus adjustment.

So, you hung your Siemens focus chart on the wall about 12ft away with no closer objects in camera view to your side.
If it's using the center only, I imagine the distance and focus chart size are important.
Did the procedure outline the correct siemens chart size?

Steven,

Firstly, I am not sure that the camera looks at the center only - it's just a hunch and would make sense to me.

I hung the Siemens "bullet" (8.5x11) on the wall about 12 feet away an centered it in frame (fully zoomed in) and focused manually on it. Then I executed the menu item. I did have a few pieces of furniture and a fireplace at the periphery of frame (at full wide).

I don't really think the camera cares what the size is, or even what the chart looks like - it's only trying to find a sharp focus (as the camera's autofocus does) that stays sharp during the entire zoom range. It seems to do an iterative autofocus, but instead of changing the lens focus, it is changing the back focus. The bullet is a very easy target to establish that initial focus with, so I would recommend using it.

I really don't know what the algorithm is really doing, but it ultimately establishes a focus that stays sharp the whole way. All the rest is conjecture on my part.

Thanks Eric, sounds right to me.

Steven,

I really don't know what the algorithm is really doing, but it ultimately establishes a focus that stays sharp the whole way. All the rest is conjecture on my part.

We know that the lens is servo-focussed - even with the focus ring in the manual position, no objectives move if the power is off and sliding the ring to the manual position 'snaps' the focus to that range. This is different to zoom, where glass is directly geared to the ring and does move with the power off.

So the focus commanded by the ring is converted into the positions of the elements by way of some algorithm or (more likely) look up table which also takes into account the zoom position and probably contributes to the CAC setting. The backfocus adjustment will get a focus at telephoto, then repeat as it zooms out to calibrated the lookup table.

AIUI!

Nick

Can anyone please give a brief explanation/guess what the camera does when it performs this backfocus adjustment procedure?

Just confirming that I did use an A4 sized back focus chart.

This one

http://www.rondexter.com/professional/equipment/focus_pattern.htm

for those that want to find it. I printed it out on a high quality printer to get as sharp as possible (although I doubt that this made any difference).


As Eric has described it is amazingly simple and totally automated - sure beats the old manual method. I did my adjustment on a white wall with only the chart in centre view at a distance of about 3.5 meters.

OK, I ran the backfocus routine with no issues, however, my problem was not resolved. Again, manual focus mode, iris wide open, zoom into a distant object, focus, zoom out wide, the entire image is still very soft, progressively softer the wider I zoom. Something else is going on here.

If you have an early camera like mine (#12), I suggest you check this out if you haven't already (especially if you are in the US with a 90 day warranty). I never noticed until I tested by lowering the f-stop to wide open. It's difficult to spot at any other stop.

Another odd thing is that when focus is set all the way to the stop at the infinity side while zoomed wide, I must pull focus back just inside the ∞ symbol to around the 8 meter mark for proper infinity focus. If I zoom in to a distant object, focus, and then zoom wide, I must roll focus all the way to the .8 meter mark for sharp infinity focus. I hope this makes sense.

One more thing. The focus ring actually travels beyond the midpoint of the ∞ symbol to the outside right edge of it. Is this normal? If I remember correctly, pro lenses always stopped in the middle of the symbol.

I've got to ship the camera back anyway for minor vignetting, so hopefully they can address these other problems at the same time.

OK, I ran the backfocus routine with no issues, however, my problem was not resolved. Again, manual focus mode, iris wide open, zoom into a distant object, focus, zoom out wide, the entire image is still very soft, progressively softer the wider I zoom. Something else is going on here.

If you have an early camera like mine (#12), I suggest you check this out if you haven't already (especially if you are in the US with a 90 day warranty). I never noticed until I tested by lowering the f-stop to wide open. It's difficult to spot at any other stop.

Another odd thing is that when focus is set all the way to the stop at the infinity side while zoomed wide, I must pull focus back just inside the ∞ symbol to around the 8 meter mark for proper infinity focus. If I zoom in to a distant object, focus, and then zoom wide, I must roll focus all the way to the .8 meter mark for sharp infinity focus. I hope this makes sense.

One more thing. The focus ring actually travels beyond the midpoint of the ∞ symbol to the outside right edge of it. Is this normal? If I remember correctly, pro lenses always stopped in the middle of the symbol.

I've got to ship the camera back anyway for minor vignetting, so hopefully they can address these other problems at the same time.


Bill, I have exactly the same problem with you, and I tried the backfocus adjustment, and nothing changed at first time. But I tried several times again with various distance to the chart, and I forgot what's the best distance, but finally it fixed. Was I just lucky?

Good hear you were able to correct it, Mooho. I'm wondering if 12 meters would be a more appropriate distance to perform the FB routine instead of 12 feet. May need a larger chart than A4 size, though.

Good hear you were able to correct it, Mooho. I'm wondering if 12 meters would be a more appropriate distance to perform the FB routine instead of 12 feet. May need a larger chart than A4 size, though.

Bill, I once tried the adjustment to the scenary out of the window (100 feet or so), and the result was much worse than original. (of course..) I'm not sure the distance of my final adjustment but maybe it was about 5m.. Although I just use A4 size chart, the result was quite obvious. I can show you the image befor-and-after when I return to home. The image softness of full-wide, full-open case was really a headache for me, and I guessed it was the limitation of the lens performance.. Frustrated.. But after the adjustment, I'm really happy. Crystal clear through All the aperture size, All the zoom range. Great!!

Another odd thing is that when focus is set all the way to the stop at the infinity side while zoomed wide, I must pull focus back just inside the ∞ symbol to around the 8 meter mark for proper infinity focus. If I zoom in to a distant object, focus, and then zoom wide, I must roll focus all the way to the .8 meter mark for sharp infinity focus. I hope this makes sense.

One more thing. The focus ring actually travels beyond the midpoint of the ∞ symbol to the outside right edge of it. Is this normal? If I remember correctly, pro lenses always stopped in the middle of the symbol.

Page 47 of the camera manual says "The infinity position has some margin to compensate for focus changes caused by variation in ambient temperature. When shooting an image at infinity in MF or Full MF mode, adjust the focus whilst observing the image on the LCD monitor/EVF screen." So the focus markings have some lattitude - it will be interesting to see whether your replacement/repaired camera has tighter tolerances.

Nick

I am beginning to doubt the quality control of Sony's prosumer units. (Never heard/read about backfocus problems of Sony/Canon consumer HDV camcorders before.)

Please see these images:

http://www.moohobae.com/mine/test/EX1_backfocus_Adj/after2.bmp

http://www.moohobae.com/mine/test/EX1_backfocus_Adj/before2.bmp

The conditions of the two images are not the same because of the different day, different time, etc.., but I tried my best to match.

Frame grab : original MP4 --> MXF by using clip browser 1.1 --> .AVI by using NeoHD --> .BMP by using Premiere Pro 2.0.

Mohoo,

What were the f/stops for each of those? The sunny one seems to exhibit some diffraction softening (rather than or perhaps in addition to backfocus softening) which becomes quite obvious on the EX1 at f/11 and above.

Mohoo,

What were the f/stops for each of those? The sunny one seems to exhibit some diffraction softening (rather than or perhaps in addition to backfocus softening) which becomes quite obvious on the EX1 at f/11 and above.

Eric, I see what you mean. But these two images were shot with the iris opened(=f/1.9),( as we discussed in this thread) and with ND2 filter.

Edit: if you used about f/3 or smaller aperture, maybe you cannot see any differences between the images before and after.

Fair enough.

Looks like a definite improvement in sharpness.

I found a clip which can show a really fair comparison. But it's not befor and after comparison. It just shows the simtom before the adjustment. You can see the problem by these images. I found this simptom just before when I shot this clip(2007-12-20 morning). This problem is now fixed for myself, because it was Christmas season, so I don't loose my important shooting chance. Maybe Bill experenced the same thing, I guess.

Please see these frame graps form a single clip.

focla length of 0.8m:

http://www.moohobae.com/mine/test/EX1_backfocus_Adj/before_focus%3d0.8m.bmp

focal length of 40m (This should be the best)

http://www.moohobae.com/mine/test/EX1_backfocus_Adj/before_focus%3d40m.bmp

Mooho, thanks for posting the comparison images. Your back-focus issue was much more subtle than what I am experiencing at f 1.9 (imagine 180º out), leading me to believe that my issue won't be resolved so easily. I may execute another FB from a different distance, but I am not optimistic.

Well, I've been without my EX1 for two weeks, as it has been enjoying a holiday at the San Jose repair center. Today, I was able to get a few answers.

The good news is that they have been able to replicate the focus problem. The bad news is they are in correspondence with Japan attempting to determine what is causing it. I was told to call back at the end of the week and maybe they could tell me more. After protesting, I received a call back from the product manager who promised to call me tomorrow upon speaking with the technician. I don't expect there is much more he will be able to tell me until they hear back from Japan.

In spite of their seemingly sincere efforts to find a solution, it is apparent that it may be a while, if ever, before they will be able to repair the defective unit. I've already turned down a nice gig this week and this delay is really putting me in a bind.

My questions are, at what point should I expect Sony to step up and simply replace it with a new one? And whom might I contact at Sony that would have the authority to make such a decision? Given their uncertainty of the what what the fix might be and no estimate of when I might expect to have it back, sending me a replacement unit right away seems reasonable. Agree?

I think Sony should provide a replacement immediately.

I think they will if you press them - but they probably won't until you do.

Thanks, Eric. I'll try to chase this down tomorrow.

And I think you should contact customer service types rather than the technicians - they'll see the big picture of the issue: That you bought a brand new camera that has never worked correctly for you and that you are a professional for whom every day without it costs you money.

I just received my camera back from Sony repair for vignette adjustment and focus tracking.

Would someone humor me and perform the following focus test? Before exchanging for a new unit, I want to be very sure my symptoms are unique.

One important detail of the required set-up that I neglected to mention before is that the light level must low enough to indicate "low light" in the viewfinder for this symptom to reveal itself. Use ND filters if required.

Full manual iris/focus/gain/etc, iris wide open, 1080/30p, -3db gain, shutter off, low-light indicator in viewfinder, zoom to a very distant object (100 yards away or so), focus, zoom wide. Focal point still in focus? Anything still in focus? Not so here.

One other question, if I may. Using the above camera settings, is infinity truly in focus when the focus ring is resting against the ∞ stop? Not with mine.

Any feedback will be very much appreciated.

Via another thread, I learned how to access the maintenance menu to set backfocus. Bill


LINK to this thread please

LINK to this thread please

http://www.dvinfo.net/conf/showthread.php?t=110220

A ran the backfocus routine before returning for repair. Sony did same, but no improvement.

Is there any chance that running the back focus adjustment will cause problems with my warranty. I am attempting to exchange my camera for another since it is still showing an obvious vignette issue even after I sent it to California.

Thanks

Charles - I doubt that it will cause a warranty problem, but I also doubt that it will fix your issue - but it is very painless and works perfectly. Certainly worth a try.

I did it on my first camera which had vignetting and it did nothing (except ensure that the back focus was correct). Having said that your vignetting seems different to most of the others that have been mentioned.

Luckily my second camera is perfect.

Thanks Graeme

The back focus is correct the BF. I am not thinking it will help the vignetting.

The telephoto vignette has been confirmed by a couple of others but definitely different from the other reports.

I just want to be sure that there are EX1's that are working properly before I talk to my dealer again. So you EX shows now shadowing at all fully zoomed in? Mine looks like I have a tele extender on it with the zoom pulled back just enough to see a barrel shadow.

I've posted a short example of the obvious focus-tracking issue. A low light reading on the camera doesn't appear to be necessary. Ignore the cadence mismatch that Vimeo encoding introduced.

http://www.vimeo.com/642741

For the last few frames, I rolled the focus all the way around to the 2.7ft/.8m range index. Notice how much sharper it gets at this strange focus setting.

So, can anyone tell me if you are able to reproduce this with the setup as described above? I'd like to know either way. The U.S. 90 day parts/labor warranty is a short fuse and it's difficult to believe mine is the only one.