Today’s Question: I’ve heard it may not be a good thing to delete shots from the memory card while it’s in the camera body. Does this hurt the card or the camera?
Tim’s Quick Answer: Deleting photos from a media card in the camera does not harm the camera or the media card. It is perfectly safe to delete images directly on the camera.
More Detail: I have frequently gotten this question from photographers, and have heard more than a few people give the advice that deleting in the camera could lead to corrupted images or damage to the media card. That is not true.
Media cards (and cameras) have gotten quite sophisticated, and do a very good job of managing the data stored on the media card. In many respects a media card functions very similar to a traditional hard drive, though with obvious differences based on the different storage media involved.
With these types of storage devices, when a file is deleted the space it was occupying is marked as being available. Other files can then be written in that space on the media. With both hard drives and flash-based media, a single file might be spread across a number of non-contiguous areas of the media. I suspect this attribute of media card storage may be what causes some to conclude that deleting files could lead to file corruption.
Rest assured it is perfectly safe to delete files from a media card directly on your camera. Deleting on the camera can also be helpful, both in terms of freeing up space on the card and deleting outtakes before you get back to your computer. Just be sure you don’t miss a great photo opportunity because you were busy reviewing photos on the back of the camera!