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7D and CF card reader question

David DiNisco , May 21, 2010; 09:50 a.m.

I have an SanDisk Extreme CF card and a Canon 7D camera. I am off loading my photos to my computer via a Zeikos 57 in 1 memory card reader. Reading the images works great. However when I put the card back into the camera it is not recognized and say I must reformat the card. Reformatting works fine. But my question is what is happening here? Should I get a different card reader?



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Jay DeSimone , May 21, 2010; 09:54 a.m.

I've never had that problem with my card reader...how are you downloading the files? Does your software remove the files and folders from the card, or just copy them?

Of course, if you don't mind formatting the card every time, there's no reason to change anything.

Peter Y , May 21, 2010; 10:12 a.m.

What software are you using to transfer the images via the card reader? Also what type of computer.. MAC or PC?
Is it possible, you aren't ejecting the card before removing it?

David DiNisco , May 21, 2010; 10:19 a.m.

I am using a Mac with Snow Leopard, and just doing a Finder copy. And I do eject the card when done. I am not deleting the files from the card...I like to keep them there as a backup if I am on the road. But I can't since I can't shoot any more photos without reformatting.

Peter Y , May 21, 2010; 10:39 a.m.

Sorry PC user can't be of much help...

Manuel Barrera , May 21, 2010; 10:49 a.m.

I do not use mac, but is it possible that your system is formatting the disc after down loading.

Robert Turner , May 21, 2010; 11:24 a.m.

I'm a Mac user as well with a similar setup (Lexar FW400 reader, 7d). I've NEVER had that happen. Next time it does, prior to reformatting in your Canon body, re-insert in the CF reader, go to Finder, and select "Get info" for the CF card. See if for whatever reason Max OS reformatted after copying in its native OS (which is not FAT based and would not be recognized by your 7d). If that is the case, then figure out what piece of software thinks its a good idea to do this. I can't imagine it is the CF reader's fault, but it is weird, regardless...

Frank Skomial , May 21, 2010; 01:04 p.m.

The card reader just by reading contents could alter something on the card, e.g. installs there a file that lists files progress that were already transferred. This is useful if there is a need to complete transfer after unexpected interaction. Some older Canon cameras allow that and work with it OK.

However, some cameras do not folerate "foreign" origin files, and instantly complain sbout it. I encountered this few times, with the many cameras I used. If your files were not transfered yet, use a recovery software like Rescue PRO or similar, and recover all files before reformating the card.

This is quite common behavior of many card readers drivers and supported software. Some cameras are smart to ignore extra contents.

David DiNisco , May 21, 2010; 02:34 p.m.

When I mount the reader on the Mac using only SnowLeopard (no other applications) the GetInfo indicates that it is formatted as MS-DOS (FAT32). So is it changing the format from the CanonOS?

Frank Skomial , May 21, 2010; 03:36 p.m.

This is just a guess, and may not be true...
I do not think the format changes. However, upon insertion of a card into a camera, the camera performs some "sanity" chacks on the card, and possibly finds extra files that were placed there by the reader and not properly accounted for in the directory list. Or the file cyclick redundancy check for the extra file is missing or not matching, or the file format is totally unknown and not unacceptable by the camera check, or ?

Once you know the behavior, try to avoid it. E.g. use USB cable, or a better card reader?

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