Peter Branch Posted July 6, 2015 Share #1 Posted July 6, 2015 Advertisement (gone after registration) I have encountered a problem with pictures taken using my M240 with a SanDisk Extreme Pro 16 GB card rated at 95 Mb/sec. Essentially of the approximately 500 DNG Compressed image files on the card about 1%, when read using Photoshop CS6 Bridge, show an image taken sometime in the past prior to the disk being formatted, sometimes more than once. There is no apparent pattern as to which image will be lost. When CS6 first reads the image file the low quality picture initially displayed on the screen is correct. However after about 10 seconds that image is replaced by a high quality version of an old image which I thought had long ago been expunged. The camera always displays the correct image in Play Mode and my JOBO GIGA Vu SONIC also always displays the correct image. The image number and metadata are always consistent with the correct image. My routine is to download images from a locked SD card into the computer. I always use the eject function prior to removal. I then store the card, still locked, until I need to use it again, (I rotate cards systematically), when I unlock it and format it in the camera. At no point do I delete any images. I’m concerned to understand what is likely to be the cause. Is it a faulty card which needs to be discarded or could it be that the camera is not writing files correctly to the SD card? Link to post Share on other sites More sharing options...
Advertisement Posted July 6, 2015 Posted July 6, 2015 Hi Peter Branch, Take a look here Lost Images. I'm sure you'll find what you were looking for!
jaapv Posted July 6, 2015 Share #2 Posted July 6, 2015 It is almost certainly a faulty card. You could try to restore it with an overwrite in SD Formatter, but personally I would just bin it. Try the new Lexar Pro 16 GB 1000x. I am very much taken with it. Link to post Share on other sites More sharing options...
Exodies Posted July 6, 2015 Share #3 Posted July 6, 2015 Shirley not, Jaap - it's the Adobe bug where old previews are used if the file name has been seen before. Zooming in and out of an incorrect preview should show the correct picture. It's a cosmetic problem only as the dng is not damaged. I think you could avoid seeing it by: Copy the images to your computer. Put the card back in the camera. Switch on the camera and format the card ready for use. If you want another copy of the pictures for security, don't keep them on the card, re-copy them to your computer after step 1. This method avoids duplicate file names; your procedure guarantees them. Link to post Share on other sites More sharing options...
jaapv Posted July 6, 2015 Share #4 Posted July 6, 2015 That is a new one to me; thanks. I probably have never seen it because I use either the importer from Bridge or Imageingester. Both organize the images by day and add the date to the file name, besides adding copyright information to the EXIF. One learns something new every day. Link to post Share on other sites More sharing options...
CheshireCat Posted July 6, 2015 Share #5 Posted July 6, 2015 Let me fix it for you: It is almost certainly NOT a faulty card. Link to post Share on other sites More sharing options...
jaapv Posted July 6, 2015 Share #6 Posted July 6, 2015 Yes-that is what Geoffey said. Link to post Share on other sites More sharing options...
Guest JonathanP Posted July 6, 2015 Share #7 Posted July 6, 2015 Advertisement (gone after registration) http://www.l-camera-forum.com/topic/243584-m240-or-memory-card-overwrites-when-it-shouldnt/?p=2797970 I slightly hesitate to post this as I think I might get a reputation for just moaning about Leica software, but here goes: this isn't a Lightroom bug, its a problem with Leica not implementing the DNG specification properly in the M240 - see http://www.l-camera-forum.com/topic/200020-leica-m-240-image-unique-id/?p=2665132 The problem is the good old ImageUniqueId and RawDataUniqueId's in the DNG exif - these are supposed to provide a unique identifier for each image which Lightroom and Bridge use to manage their preview cache (thus avoiding any problems with duplicate file names). In previous cameras, Leica used an encoding of the shutter activation count which did result in a unique enough number that you won't see this problem with the M9. For whatever reason, in the M240 the shutter count was removed from the unique image IDs and replaced with a time-based count that is reset whenever the camera is powered off. So its now possible to get 2 images with the same ID, which is what confuses the Lightroom cache and ends up displaying the wrong preview (going into develop module should show you the real preview). This is fixable via ExifTool, or you can use my 'green shadows' plugin to fix rogue images - it will replace the image IDs in the output file with proper unique image digests. My work-around to reduce this is to only switch my camera power off when putting it away in the bag, and just let it power save when carrying around - the power save doesn't reset the counter. Sometimes it feels like a bit of a stuck record, but I just wish Leica would polish off these few remaining M240 bugs If there's anyone listening, then a quick fix to the M240 s/w could be a simple as using the date hashed into the IDs? Just a thought... I think its this issue that I bump into every so often with Lightroom, but suspect Bridge has similar side effects. You should find if you edit the actual file you will end up with the correct image. I do wish Leica would fix this bug, it wouldn't be hard to fix. Basically its Leica not implementing the DNG spec correctly, so its not the fault of Lightroom or Bridge that you see these old previews from their cache. Jonathan Link to post Share on other sites More sharing options...
lct Posted July 6, 2015 Share #8 Posted July 6, 2015 Jonathan, did you draw Leica's attention to your finding? Just curious. Link to post Share on other sites More sharing options...
CheshireCat Posted July 6, 2015 Share #9 Posted July 6, 2015 Basically its Leica not implementing the DNG spec correctly, so its not the fault of Lightroom or Bridge that you see these old previews from their cache. Indeed. But everyone should use lossless-compressed DNG on the M240, and if Adobe engineers did their homework right, they would also check if the file size mismatches with the one recorded in the cache. Is the OP using lossless-compresed DNG ? Link to post Share on other sites More sharing options...
CheshireCat Posted July 6, 2015 Share #10 Posted July 6, 2015 Jonathan, did you draw Leica's attention to your finding? Just curious. This should not be necessary, as I expect someone in Leica to monitor each and every thread in this forum (and not only). ... well, at least this is what good companies do. Link to post Share on other sites More sharing options...
Guest JonathanP Posted July 6, 2015 Share #11 Posted July 6, 2015 Jonathan, did you draw Leica's attention to your finding? Just curious. I haven't managed to find a direct way of reporting software bugs - if anyone wants to PM me any contact details that would be much appreciated (alternatively if anyone who might be beta testing would like to report my findings above that would also be great!). But everyone should use lossless-compressed DNG on the M240, and if Adobe engineers did their homework right, they would also check if the file size mismatches with the one recorded in the cache. Unfortunately I don't think that would help in this case since the cache contains the rendered preview not the original file (thats why when you go into development module in Lightroom and make a tweak the cache is updated with the preview for the image you are working on, and you'll find the other image with the same unique ID in your library will now show the new file preview). I'm guessing Adobe uses the unique ID as the index into the preview cache, which allows file moving and renaming without having to track those changes in the preview cache. Link to post Share on other sites More sharing options...
pico Posted July 6, 2015 Share #12 Posted July 6, 2015 It might be related to poor file naming conventions on the Leica. In Bridge, try this. It might help. Link to post Share on other sites More sharing options...
CheshireCat Posted July 6, 2015 Share #13 Posted July 6, 2015 Unfortunately I don't think that would help in this case since the cache contains the rendered preview not the original file (thats why when you go into development module in Lightroom and make a tweak the cache is updated with the preview for the image you are working on, and you'll find the other image with the same unique ID in your library will now show the new file preview). I'm guessing Adobe uses the unique ID as the index into the preview cache, which allows file moving and renaming without having to track those changes in the preview cache. What I mean is: - Save also the original file size (a few bytes) in the cache entry - If an imported file matches a unique ID in the cache, but the size mismatches, prompt the user asking whether to replace the previous file or keep both (i.e. a proper unique ID will be generated). Even better, instead of the size, use a hash on the decompressed data, so this would work also for uncompressed DNG. Link to post Share on other sites More sharing options...
Guest JonathanP Posted July 6, 2015 Share #14 Posted July 6, 2015 What I mean is: ... Sorry, yes of course. If I was designing it I would have all that info in the catalogue database, then for each image create a UUID that I would use as the index into the preview cache. That way the internal operation/optimisation of Lightroom would not be dependent on any external file attributes Link to post Share on other sites More sharing options...
Peter Branch Posted July 6, 2015 Author Share #15 Posted July 6, 2015 Is the OP using lossless-compresed DNG ? Yes. Link to post Share on other sites More sharing options...
Peter Branch Posted July 6, 2015 Author Share #16 Posted July 6, 2015 ....... You should find if you edit the actual file you will end up with the correct image. I do wish Leica would fix this bug, it wouldn't be hard to fix. Basically its Leica not implementing the DNG spec correctly, so its not the fault of Lightroom or Bridge that you see these old previews from their cache. Jonathan This seems to be correct. Thank you. If I use ACR 9.0 on the "wrong" DNG image as shown in the PS Bridge preview then it initially displays the "wrong" image but after a short while it changes to a high quality image of the correct file. I've been able to recover all the pictures this way. Link to post Share on other sites More sharing options...
Peter Branch Posted July 6, 2015 Author Share #17 Posted July 6, 2015 Shirley not, Jaap - it's the Adobe bug where old previews are used if the file name has been seen before. Zooming in and out of an incorrect preview should show the correct picture. It's a cosmetic problem only as the dng is not damaged. I think you could avoid seeing it by: Copy the images to your computer. Put the card back in the camera. Switch on the camera and format the card ready for use. If you want another copy of the pictures for security, don't keep them on the card, re-copy them to your computer after step 1. This method avoids duplicate file names; your procedure guarantees them. I will change my routine to the one you suggest. Thank you. Link to post Share on other sites More sharing options...
Peter Kilmister Posted July 6, 2015 Share #18 Posted July 6, 2015 @Exodies: Who is this Shirley? Do you mean surely? Link to post Share on other sites More sharing options...
Exodies Posted July 6, 2015 Share #19 Posted July 6, 2015 Sometimes silly jokes stick in my head and need overuse to shake them out Link to post Share on other sites More sharing options...
jdlaing Posted July 7, 2015 Share #20 Posted July 7, 2015 Shirley you jest. Link to post Share on other sites More sharing options...
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