Odd CF card issue
 

I've had my 7D for two weeks, and couldn't be happier. I've got a SanDisk 8gb CF card.

I updated the firmware on my 7d from 1.2.1 to 1.2.2. Then reformatted the card. Didn't need to, just playing around with the camera and the card ( I had already copied all the pictures on the card to my pc).

I then shot a little bit of video with the camera. I took the CF card out of the camera and put in the card reader - and the pc couldn't read it. On my laptop I got an error message saying 'semaphore timeout has expired'. Tried different USB ports, same thing.

Googling 'semaphore timeout has expired' suggested the card is corrupted. I guess that's possible, I've only had the card for two weeks.

Curiously, the camera still records to the card, and when I attach the camera to the computer, I have no problem getting stuff off the card. Did the camera format the card with some weird format Windows can't read?

The card worked fine without being formatted in the camera - is formatting in the camera a no-no?

Formatting in the camera is good. Some say you should always do that. Have you tried a different card reader? The fact that it works from the camera to the computer seems to imply the card reader is bad.

My next step was to get a new card reader, maybe a new 4gb card.

Googling the error message, I found a few forums where people said these cards fail frequently. One person said they only buy 4gb cards, since a corrupted 32gb card would be a waste of money.

Is that other people's experience? 'Often' is a subjective term, but do other people keep a bunch of 4gb cards around, and avoid larger sized cards? I know the camera stops when the file is 4gb, but I was thinking I'd have two 16gb cards, and fill one with 4gb chunks. While that's being offloaded, pop the other card in.

SanDisk CF and SDHC media seem to have the fewest problems. You may have gotten one that's bad so I'd suggest buying another like it (from B&H or from amazon where amazon is the actual seller) and send the bad one back to SanDisk since you've only had it two weeks.

However, if you got it as a "bargain" (such as off ebay) and not from a reputable dealer like B&H be prepared...SanDisk may come back with a "Not one of ours" response. There are a lot of counterfeit SanDisk media out there especially on ebay. I've even seen some listings on amazon from associated sellers that look questionable to me.

My SanDisk 8GB Extreme CF cards were purchased from B&H. I "choked" a bit at the price but placed the order, each time for just one card until I had 3 of them. But I've not had a corrupted or lost file yet.

Got my CF card at BestBuy.

We're using 32GB Sandisk cards and haven't had any issues yet (knock on wood). When we switched to DSLR's we did a lot of research on the cards and Sandisk seemed to be the #1 choice, and we never any information that larger cards were more prone to issues. So take that for what it's worth.

Regarding 4GB cards, I think they would work fine depending on what you are shooting. We shoot primarily weddings, so a 4GB card is not ideal since we would have to switch cards far too often. But if you're shooting set shots for a controlled production I could see a 4GB card working just fine.

This card business is kind of interesting, in terms of what result people are getting.

Last year when I bought my Canon 5d, I bought 2 8 gig and 2 16 gig, Kingston cards, that I am sure many thought were not suitable. I have never had an issue with them.

Similarly, I recently bought the T2i, and outfitted it with lower class SDHD card , that seem to do the duty, despite higher class recommendations. Not noting any issues. Sometimes I wonder if manufactures make the same card for all levels, but label and price them differently..

Looks like it was the card reader. Didn't think they'd be that delicate.

But I'd rather it was the card reader than cards full of uncopied footage going down the crapper.

Thanks for the update. Glad it was just the reader.