Deleting and Formatting memory card

[patchen]

Hi - I attended a photography workshop recently, and the instructor advised that we never delete files using the camera - rather we should use the camera to format the card after we copy the pics to computer. I have always moved pics from the memory card to my PC, and thus clearing the card, but was told I shouldn't do this.

I wanted to get other's opinions on this... thanks!

[autofocus]

Originally Posted by patchen

Hi - I attended a photography workshop recently, and the instructor advised that we never delete files using the camera - rather we should use the camera to format the card after we copy the pics to computer. I have always moved pics from the memory card to my PC, and thus clearing the card, but was told I shouldn't do this.

I wanted to get other's opinions on this... thanks!

I always use the format function. I believe deletes will leave some un-viewable data behind, whereas a format does a total clean

[dakwegmo]

Lexar seems to suggest the same thing. From their Memory Card Tips

Deleting images in the camera is a convenience but at the same time can result in data corruption, especially with large file formats like RAW and TIFF files. ... Once the files are moved, it is recommended to initialize your Lexar memory card.

[jdepould]

Regardless of whether you do a move or copy to download the images, you should format the card in-camera.

Deleting an image right after you take it isn't really a big deal, the bigger problems happen when you're deleting images in the middle of all your other images. This can lead to truncated (corrupted) files.

[dlambert]

I saw a couple of cases where I used a card half-way, copied photos off, deleted the photos, put the card back into my 30D, and it reported the card was still at half capacity. That was enough to get me in the habit of formatting. Typically, I'll hit "play" on the camera to confirm there aren't photos on the card, then format it and go.

[audiman90]

I always delete my images after transferring them to my computer. I have never had a problem yet.
After reading this thread I formated my card in camera then put it through file recovery program and it recovered over 100 images all of which were usable.
When I formatted the card it only took a couple of seconds which suggests to me that it only removes the headers. If it did a full format it would take several minutes, according to the size of course.
When you delete the files in camera it only knocks out the file headers. When you format in camera it knocks out the file system by overwriting it, then writes a new file system still leaving the files there.
I would suggest that formatting your card in the camera is no better than deleting the files in camera.
If however you delete your files and your folders in your computer the you will need to format the card in camera.