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Author Topic: Camera -Compact Flash cards  (Read 50505 times)
Fred A
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« on: July 25, 2009, 12:05:05 PM »

I have a question that always bugs me regarding CF cards and formatting them.
Years ago, when I dabbled in DOS, a deleted file was actually still on the disk with DOS replacing the first character of the file name with a $, rendering the file invisible.
I had an editor program that would read the disk and if I replaced the $ with any other letter, I got my deleted file back.
If that file was deleted recently, it was likely that the recovered file was in pristine condition. If it was deleted a while ago, where other data could overwrite it, then the recovery might be flawed and some corruption of mixed data would appear.

OK all that aside, I have tried this many times.... I take my CF card from my camera, and FORMAT it in the camera or in the computer (Fat 32) and I can still recover all the images from that card using a little digital image recovery app.
Is it possible that the Format procedure is doing that old "delete" thing and hiding the image files?
I thought formatting would "clean" out the card for a fresh new start???

I really would like to understand this.
Fred
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Seth
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« Reply #1 on: July 25, 2009, 12:30:04 PM »

Fred-

It is still doing the DOS (FAT) format header.  In fact, you can put the card in your PC, do an NTFS format, go back to the camera, format again and still recover.  I have tried doing five formats in a row, with different FAT and sector sizes, then was still able to recover.

I us Photo Rescue which is pretty intense.  They do have a free program at their site that will wipe the card.

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Seth
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« Reply #2 on: July 25, 2009, 02:37:26 PM »

While this is something I never really worry about, I have noticed that I can recover images from some cameras but not others.  I've tried several undelete programs and none of them can ever undelete a photo from my little Sony pocket camera (T5) even if you try it right after the delete before any other pics are taken.  Other cameras work fine.  I wonder if it's just something different regarding Sony's Memory Sticks or if the camera actually wipes the files?

Mike
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BrianPrice
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« Reply #3 on: July 27, 2009, 07:58:16 AM »

Mike
The early Kodak cameras (including some of their dslrs) did this as well, they seemed to shred the files instead of just deleting or 'formatting' the card. I don't think it's the same formatting that you do to your hard disc, perhaps this is what Sony are doing.

Brian
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hedwards
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« Reply #4 on: October 11, 2009, 02:54:00 PM »

Fred-

It is still doing the DOS (FAT) format header.  In fact, you can put the card in your PC, do an NTFS format, go back to the camera, format again and still recover.  I have tried doing five formats in a row, with different FAT and sector sizes, then was still able to recover.

I us Photo Rescue which is pretty intense.  They do have a free program at their site that will wipe the card.


I believe that depends somewhat on the type of formatting one does. With CF cards you should be doing a quick format, as in the format only touches parts of the disk necessary to declare it newly formatted, leaving most of the card completely untouched. Theoretically a format of that sort could be repeated as many times as one likes without damaging the data on the disk.

However that would not be the case if one were writing to every sector of the disk during the case of the format. While one can theoretically get data back after writing zeros to the whole disk, it does become a more risky proposition and at that point you may or may not be able to recover.

In the case you're mentioning, the key thing is that the filesystem information land in the same place each and every time, as any decent file recovery tool will allow you to ignore the FAT and do a sector by sector search for things that look like files.
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hassanrok
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« Reply #5 on: April 14, 2010, 09:20:34 AM »

I use flash cards to remind me of many of these variables and also specific troubles i've been having when i'm shooting. These flash cards are very custom to where i'm personally at with my photography.  For example "Check the edges for any distracting/unneccessary elements"   This is easy to say, but making it a habit in the field may take some time. So i carry a set of flash cards with me while shooting and when i've got some down time, i flip through them. Lips sealed
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stephen144
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« Reply #6 on: May 17, 2011, 04:35:51 PM »

Hi
I used Bruce Fraser, shortly before he died, was taking this on and showing that jpegs have more info in them than originally believed.  When the new ACR came out in CS3 (?) allowing it to grab JPGs, the Recovery was saving some highlights previously thought lost.  Speculars are gone immediately.

Of course, Nikon, Canon, Sony and Olympus share some of the credit as they reduced blooming since the old days of D1/2 and the Canon Mark xxx.

Although I have never DL'd a card, put it back in the box and tried to compare Histograms against LR, PS or QI, I am guessing the cameras are not as accurate.  At the least tey are harder to eval in that 2.5-3" they give us.  The most I look for in the box is whether I am crunching either end or just bumping it.
« Last Edit: May 17, 2011, 04:37:28 PM by stephen144 » Logged

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