Wednesday, August 6, 2008

Photorec Rocks

A couple months ago I had some images go corrupt on my CF card (how does that happen? more on that at the end of this post). I tried the RescuePRO software that came with my SanDisk Extreme III cards, but while I have been more than pleased with the cards, the software was a bust. Doesn't have the ability to recover raw image files. Hnn?! If I had shot in jpeg, it'd have made an effort at recovery, but I don't shoot in jpeg.

So what to do ?

I did some pokin' around the internet and came across somewhere (I think it was a forum at a recommendation for Photorec, a free program written by Christophe Grenier. While it's free, donations are accepted. On a Mac (OS X), it runs in Terminal, so it isn't pretty, but it rocks. There are also versions available for Dos (?), Windows, Linux, Unix, BSD, and OS/2. Click here to download the version you need.

Photorec even recovered a few files from over a year ago, and I've shot thousands of images on this card since then, and formatted the card dozens of times. Not sure how that works. Although, some of the images from my recent shoot, the one's that got corrupted, were lost. I gather that's not a fault of the software, but simply that some of the images were corrupt beyond saving.

If you're not geek enough to understand the selections you need to make in Photorec in order to recover your images, there's a step by step guide. If you're not geek enough to understand the step by step guide you can email Christophe. I did, and he responded within twelve hours. (Tip: when you get to the point where you need to choose which directory to save your images to, select a directory, then press the Y key.)


After downloading Photorec:

1. I unzipped the file called "testdisk-6.10.darwin.tar.bz2"

This created a folder called "testdisk-6.10" (There are two programs that are part of the download. Testdisk is one, and Photorec is the other. Both are part of the same zip file.).

2. Inside the testdisk-6.10 folder is another folder called Darwin. I opened it and clicked on the file called photorec. The Mac version I used doesn't have a pretty icon, just a gray rectangle with the word photorec next to it.

3. Upon clicking the Photorec icon, Terminal opens and you simply follow the prompts.


Here's my own step by step guide. That is, this is what I selected when I ran Photorec. Not sure if it makes any difference on some of these if I had selected another option:

Disk selection: my CF card
Partition type: none
File opt: crw [which recovered my cr2 files nicely]
For the file partition type I chose FAT.
Then I selected a directory to save the files to and pressed the Y key.


But why do files ever get corrupted?

[Edit: click here to read my post on CF card file corruption.]

I never had the problem until I got a card reader. Before then I had just plugged in my camera to my computer in order to upload images. Since I got my card reader I have now had two instances of corrupt/unreadable images, one time each on two different cards. The images were initially readable by my camera, then I took out the card, tried to upload with my card reader, and poof, corrupt images. My camera couldn't read them after that. Thankfully there's Photorec, but what caused the images to corrupt between taking the card out of my camera and trying to upload to my Mac with a card reader? I'll look into it and report what I find.

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