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Old January 5th, 2008, 03:54 PM   #436
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Zoom Does Not Track in My Vignetting Camera

One of the important adjustments in a film camera is centering the lens within the film gate - lenses need to be recentered when changing from academy to super 35 shooting for example, as the whole image is shifted to the side .05"

A quick way to test for whether a lens is centered is to put a target on the wall (a piece of tape will do), put zoom lens on the camera and zoom in and out. The target should remain centered on the crosshairs throughout the zoom range.

I tried this on my (as yet) unrepaired vignetting EX1 and found that the zoom does not "track" while zooming. A centered target at full tele shifts down and slightly to the right when zoomed full wide.

Question to all - vignetting and non vignetting camera owners. Does your zoom track? Be sure to test this with OIS off. Use the center marker on LCD for greater precision.

I think this will give a clue as to whether your lens is adjusted properly and whether your camera will vignette.

Thanks.
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Old January 5th, 2008, 04:10 PM   #437
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Quote:
Originally Posted by Eric Pascarelli View Post
Question to all - vignetting and non vignetting camera owners. Does your zoom track? Be sure to test this with OIS off. Use the center marker on LCD for greater precision.

I think this will give a clue as to whether your lens is adjusted properly and whether your camera will vignette.

Thanks.
Hmm.
I have not thought of this, I will try the test.
Also, I can only HOPE that Sony is using the SDI out when checking for this problem. This will offer them the full raster. I can't imagine they are not.
If they are relying on the LCD, you can not use this, it's to small to see the problem.

I sure got the impression they only used the LCD when I saw they turned OFF all display items for the LCD...
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Old January 6th, 2008, 09:04 AM   #438
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Just did vignetting test and zoom/track test

I just performed the vignetting test,seems mine is ok,i also performed the zoom and track test,that was also ok so maybe these two faults are linked.Has anyone else with known vignetting tried the zoom and track test ?
I was told by my retailer that my cam was from the 2nd batch.
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Old January 6th, 2008, 09:16 AM   #439
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I am sure that they are related - my lens is clearly not centered on the chip and I have the vignetting problem.

Also, there is a significant vertical error in the zoom test, and only a slight horizontal error. This is consistent with the vignetting that shows only at the top corners of the frame, and almost equally on both sides of the top.

When I zoom from tele to wide, the target (on the wall) drifts down and to the right. My vignette corners encroach on the image as if the offending circular blockage were offset in that same direction. Sounds like a predictable relationship, perhaps?
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Old January 7th, 2008, 10:00 AM   #440
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Anyone else still having the vignetting issue?

I'm still showing the problem after the adjustment.

http://dvinfo.net/conf/showpost.php?...&postcount=434
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Old January 7th, 2008, 11:08 AM   #441
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I haven't seen the problem on mine so far. I should have the 11th camera from France.

I got a hand on another one in france, and zooming to a white wall showed slight darkening on every 4 edges. Mine doesn't.
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Old January 7th, 2008, 03:18 PM   #442
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Steven,

My replacement cam is fine. I opted to have Sony Australia do the adjustment even though it was a replacement camera. I think that our local service engineers are very frustrated that the factory has let so many through QC. I know that my request for adjustment was justified as the service engineers said that the replacement camera sent to me did have a slight problem - but it is perfect now.

Looking at your adjusted camera - the vignetting seems apparent on all 4 corners and about to the same degree - which I have not seen before. Generally it is prominent in 2 only, or 3 in bad cases. Equal vignetting in all 4 corners would tend to indicate either a faulty lens or an incorrect forward/backward alignment (I don't even know if this is adjustable).

Time to get back to Sony your dealer with strong complaints.
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Old January 7th, 2008, 08:13 PM   #443
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I have brought this up with Sony. I'm waiting to hear back.
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Old January 17th, 2008, 08:24 AM   #444
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So I just got my camera from AbelCine on a fresh shipment and it seems to be exhibiting a bit of the vignetting problem.

Is there an 'acceptable' level of vignetting?

Is there such a thing as being way out of safe area with HD?

Have others here who have had this problem seen it completely go away with service and how long was the camera out of your hands?

Thanks!
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Old January 17th, 2008, 03:46 PM   #445
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Andrew,

There is no level of acceptable lens misalignment vignetting. If you are seeing the black shadows in corners at 10mm and F1.9 when following the instructions on this thread - then you have it, and should return your camera for either service or replacement. Experience is that it takes only a few days to repair, and with the exception of Steven's camera all seem to have been fixed completely.

On the other hand all lenses have a degree of vignetting as they approach their long end - and the EX1's is no exception (even if it is a really good piece of glass). There will be a slight darkening of the picture starting from the corners, but moving toward the centre as you zoom in - but this should be very slight and not really noticeable except if you are really looking carefully and focussing on a perfect white wall.
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Old January 17th, 2008, 04:48 PM   #446
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Looks like I might be in the clear. Last night when I did the test, I was going handheld in a somewhat dark studio shooting at an unevenly lit wall.

Today I did the test shooting at an overcast sky on a tripod and didn't see any but my focus wasn't set to infinity. I did the test again with focus set to infinity but by then it was much darker and a lot harder to tell.
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Old January 17th, 2008, 05:04 PM   #447
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Andrew,
It sounds like yours might be OK.

for a quick test, aim at a white wall, or ceiling.
Intentionally under expose.
f1.9 aperture
Slowly step through focal range 8-25mm.
I believe focus near infinity will enhance the vignette more (if any).
OIS off
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Old January 17th, 2008, 06:11 PM   #448
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Steven, just wondering if you resolved this issue with Sony.
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Old January 17th, 2008, 06:23 PM   #449
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Working on it. It should be resolved by next week.
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Old January 17th, 2008, 08:13 PM   #450
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I assume that when you say intentionally underexpose AND set your iris to f1.9 you would compensate (if necessary) with ND filters. Right?
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