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Author Topic: Whoa! What is this? (image corruption)  (Read 7319 times)

scott_dobry

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Whoa! What is this? (image corruption)
« on: November 10, 2008, 01:21:48 PM »

Greetings,

I'm on a Mac Power PC running OS 10.5.5 and LR 2.0.  I am shooting with a Canon 1ds III on SanDisk Extreme IV 4.0 GB cards.

Sometimes I get the following corruption on part or most of an image while working with an image in the develop mode.  I recently upgraded to LR 2.0 and was hoping that it would clear up what was happing in LR 1.0 but it has not.

The only good news is that when I restart the computer and then relaunch LR, the corruption disappears before my eyes.  In other words, when the image is "loading" in LR's develop mode, the same corruption is there momentarily but then vanishes once the image has fully loaded.

Any thoughts?  

Let me know if I can provide more information as I'm sure I have not provided enough.
[attachment=9586:LR.corruption.jpg]


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NikosR

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Whoa! What is this? (image corruption)
« Reply #1 on: November 10, 2008, 02:25:42 PM »



Maybe the problem lies with the file itself and particularly with the jpeg preview built in the file? Do Canon files contain a jpeg preview? I've seen similar with problematic cards. Have you tried a different card?
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sergio

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Whoa! What is this? (image corruption)
« Reply #2 on: November 10, 2008, 02:25:47 PM »

It is curious. It has happened to me but when an image is being recorded in camera to the card and I ran out of batteries. Looks just like what you are showing.
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scott_dobry

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Whoa! What is this? (image corruption)
« Reply #3 on: November 10, 2008, 04:55:15 PM »

Quote from: sergio
It is curious. It has happened to me but when an image is being recorded in camera to the card and I ran out of batteries. Looks just like what you are showing.


I'm doing a formal card test at the moment with several cameras/cards.

I've tried putting the card back into the camera with the corrupt image to see how the thumbnail looks on the camera display and when I do, the corruption I see in LR is not present on the camera display.

It seems to me that somehow the key to this is that a restart of the computer restores the image.

RAM?  


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Schewe

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Whoa! What is this? (image corruption)
« Reply #4 on: November 10, 2008, 05:07:24 PM »

Quote from: scott_dobry
I've tried putting the card back into the camera with the corrupt image to see how the thumbnail looks on the camera display and when I do, the corruption I see in LR is not present on the camera display.


What you have is a raw file whose RAW data is corrupted but whose EXIF JPEG thumbnail is not. What you see in the back of the camera and when viewing rough thumbnails is NOT the raw data, it's a preview that the camera made. Lightroom can show you that preview but if it needs to access the RAW data, and it's corrupt, what you end up seeing is what you are seeing.

The corrupted raw data can be caused by; pulling the card before the image has been fully written to media, faulty media, faulty transfer to the HD, HD corruption after a copy or a bad camera. The most likely is that something interfered with the actual writing of the capture on your card media. Second most likely is a bad copy to the HD which could be the card reader or cable. Third most likely is a bad card.

It's highly unlikely that the image has been corrupted by a software application since proprietary raw files are treated as Read Only files and are not actually touched. So, if the application trying to READ the file can't read it, it's toast. You can try a different card reader or cable and try copying it again but if it's toast on the card, it's toast.
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scott_dobry

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Whoa! What is this? (image corruption)
« Reply #5 on: November 10, 2008, 06:07:16 PM »

Great to have you here Jeff.

My question is, if the RAW file is corrupt, how can it be corrupt only part of the time?  Meaning, they are flawed in LR at first, but then I restart the computer and I can recover them.

I just did the card test over 4 cards.  I didn't pull the cards from the camera until they were finished writing.  I loaded them to HD all the same (Delkin FW reader into front FW jack in Power Mac).  No other apps were running at the time.  There ended up being 4 "corrupted" images out of 158 shot over 3 cards.  Each of the corruptions is unique in design (sometimes it's 10% of the image, sometimes it's 70%)  One thing that IS similar is that the flaw always comes from the lower right part of the image (as seen in the sample).  

Anyway, as usual, when I restarted the computer, I was able to recover the images.  They will now open without the flaw.  Strangely this time however, even though the thumbnail and large develop image looks good when the thumbnail is highlighted, if I switch to another image, the flaw reappears in the previous thumbnail!  Then when I click back to that thumbnail the flaw disappears and so on.

Very weird.
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Eric Myrvaagnes

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Whoa! What is this? (image corruption)
« Reply #6 on: November 10, 2008, 07:50:02 PM »

The fact that it has occurred with both LR 1.0 and 2.0, and occurs with different cards, and is intermittent, makes it sound like possibly a memory problem in your computer. I would carefully remove the memory dimms (or simms, or whatever) and clean the contacts and reinsert them. If this doesn't clear it up, try running some sort of memory test routine. I have had things somewhat similar happen to a PC a couple of times that cleared up when I cleaned and reseated the memory.

Just one more thing to try.
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Panopeeper

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Whoa! What is this? (image corruption)
« Reply #7 on: November 10, 2008, 08:00:48 PM »

Why don't you upload one sample instead of speculating about it?
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Tklimek

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Whoa! What is this? (image corruption)
« Reply #8 on: November 10, 2008, 08:08:47 PM »

Maybe a video driver issue???

Todd in Chicago

Quote from: Panopeeper
Why don't you upload one sample instead of speculating about it?
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scott_dobry

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Whoa! What is this? (image corruption)
« Reply #9 on: November 10, 2008, 10:20:19 PM »

Quote from: EricM
The fact that it has occurred with both LR 1.0 and 2.0, and occurs with different cards, and is intermittent, makes it sound like possibly a memory problem in your computer. I would carefully remove the memory dimms (or simms, or whatever) and clean the contacts and reinsert them. If this doesn't clear it up, try running some sort of memory test routine. I have had things somewhat similar happen to a PC a couple of times that cleared up when I cleaned and reseated the memory.

Just one more thing to try.



Can you recommend a RAM test?  Kelley Computing's "Remember"?

http://www.kelleycomputing.net:16080/rember/
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Eric Myrvaagnes

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Whoa! What is this? (image corruption)
« Reply #10 on: November 11, 2008, 12:00:02 AM »

Quote from: scott_dobry
Can you recommend a RAM test?  Kelley Computing's "Remember"?

http://www.kelleycomputing.net:16080/rember/
Sorry. Mine is a PC; I'm not familiar with utilities for the Mac, but the Kelley "Remember" sounds just like the kind of thing I would use on a PC.

Good luck.
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scott_dobry

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Whoa! What is this? (image corruption)
« Reply #11 on: November 11, 2008, 08:40:24 AM »

Quote from: EricM
Sorry. Mine is a PC; I'm not familiar with utilities for the Mac, but the Kelley "Remember" sounds just like the kind of thing I would use on a PC.

Good luck.

I'm using Memtest right now.  It runs in OS X's "single-user" mode and runs about 15 tests on the RAM and shows you the status of each test as it completes them.  Last night it showed accross-the-board failures in what I so far have narrowed down to 1 of 2 Crucial brand chips.  With them out I'm running a final test this morning replacing all but the Crucial (it takes a few hours to do the test).

With the bad RAM out, I'm anxious to try LR again to see if I can produce the phantom corruptions.  Hopefully NOT!


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Eric Myrvaagnes

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Whoa! What is this? (image corruption)
« Reply #12 on: November 11, 2008, 10:41:47 AM »

Quote from: scott_dobry
I'm using Memtest right now.  It runs in OS X's "single-user" mode and runs about 15 tests on the RAM and shows you the status of each test as it completes them.  Last night it showed accross-the-board failures in what I so far have narrowed down to 1 of 2 Crucial brand chips.  With them out I'm running a final test this morning replacing all but the Crucial (it takes a few hours to do the test).

With the bad RAM out, I'm anxious to try LR again to see if I can produce the phantom corruptions.  Hopefully NOT!
I hope that does fix it. RAM is cheaper than going back and trying to repeat the ruined photos.
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brianrpatterson

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Whoa! What is this? (image corruption)
« Reply #13 on: November 16, 2008, 10:39:31 AM »

If RAM proves reliable (which I wonder if it is even involved here - Mac-supplied RAM is notoriously reliable but third party video cards are another story),  I'd look at the video card and its RAM next - intermittent video problems start with intermittent video cards... have had that experience with no image corruption issues.

You can actually pull the video card out and run onboard video to check this possibility out... I think each Mac still has a basic video chip onboard, don't they? If not, forget that idea.

Hope your headache goes away soon!
« Last Edit: November 16, 2008, 10:42:53 AM by brianrpatterson »
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Pindy

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Whoa! What is this? (image corruption)
« Reply #14 on: November 16, 2008, 10:56:25 PM »

I get the exact same thing on occasion. The only difference is that if I restart, the problem persists, though I can usually re-import the image from the card and everything is fine, leading me to the conclusion that the card reader or other part of the chain going to LR2 is to blame. I noticed it first started soon after buying a Lexar FW800 card reader. I don't experience it with my Delkin ExpressCard reader or straight from the Camera via USB.


« Last Edit: November 23, 2008, 12:39:23 AM by Pindy »
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Philippe

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Whoa! What is this? (image corruption)
« Reply #15 on: November 18, 2008, 02:04:01 AM »

I had about the same problem, when I was still working on my old iMac, and downloading RAW files from a K10d connected via the USB cord.
This only occurred when I was 'doing something else' (e-mails, surfing, text...)  on the computer while the camera was uploading the files. When I stopped doing two things at the same time, the problems were gone...
No problems with the Mac pro I have now.

Philippe

dmward

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Whoa! What is this? (image corruption)
« Reply #16 on: November 18, 2008, 06:06:09 PM »

Since the corruption is a video block and can be cleared/changed by restarting the computer I would be suspicious of virtual memory paging.

If it were the video card the problem would be likely to appear anywhere on the screen rather than just the camera file image. Since Lightroom has to share memory with other applications it may be paging the RAW file into virtual memory during the image rendering process, if the virtual paging is a problem or there is a bad sector or two on your hard drive in the area reserved by the OS for paging, that may be the problem.

I'm not a computer guy, just applying troubleshooting techniques and virtual paging seems like the most transient type memory.
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scott_dobry

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Whoa! What is this? (image corruption)
« Reply #17 on: November 25, 2008, 09:29:05 AM »

UPDATE:  
After removing the broken RAM, so far I'm not experiencing any problems as previously encountered.  Coincidence?  Perhaps.  But I've not had a single corruption since (with heavy post-production use).

I'd suggest anyone still having problems look into checking their RAM with a $2 program called Memtest OSX.  My "system" indicated that my RAM was "OK" but when I used the Memtest software it detected errors in some Crucial-brand memory.  I've sent that memory back to Crucial.  We'll see if they replace it for me.

Sorry this won't help those with reader issues.  Sounds like a separate problem.
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scott_dobry

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Whoa! What is this? (image corruption)
« Reply #18 on: November 27, 2008, 08:54:36 PM »

Crucial did indeed quickly replace the bad memory with 2 new sticks.   I tested them and they check out OK.  I'll report back if I encounter any more issues with the corruption.


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blowery

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Whoa! What is this? (image corruption)
« Reply #19 on: January 03, 2009, 03:05:38 PM »

FWIW, I've seen the same thing with a number of files that worked fine in the past but recently (post LR2?) started showing this same kind of corruption. I havn't tried to narrow it down, but I do know that some files that now appear to be corrupt were the same files I made prints from back before Lightroom was available.
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