I have a Canon T3i. I was using a 16 GB memory card that came with my camera. I took photos of the children sitting in Santa's lap. Went home and looked at them on the camera. I put the memory card in my memory card wallet and then into my purse; took it out the next morning at work and inserted it into a memory card reader and then hooked that up to my camera. It showed nothing. It had some type of error in the Canon folder. I had lots of other photos on the memory card...probably 300 or more. Everything is gone. I had everything backed up except the photos with Santa, as I had just taken them. I did not do a format card or a delete all images. I can't even describe the disappointment. How did my memory card get corrupted?
But before you do anything to the card try one of the recovery software programs. SD Recovery Pro is just one of them but does a great job. It is worth a try. Some of them are free or at least free to try and see if it will work for you.
Do a serch for recover files.
I don't understand why you would hook up a memory card reader to your camera so maybe that's not what you meant to write. see
PLUS We've had many other threads on photo recovery. The absolute most important thing to do now is to STOP using that card until you're recovered the photos.
You mention having viewed the Santa photos on your camera.... I assume they looked okay.
But later when you put the card into your card reader, hooked to the computer, you could not find them and may have noted some sort of error.
You didn't say how you were viewing on the computer. Was it via some software? Perhaps Canon's or another image cataloging/editing software?
Some softwares will display images in a date-specific manner, so that you might not see the latest ones in the same place as older images.
There are more basic and simple ways to view and move/copy image files. I use a PC with Windows 7 and simply use Explorer to set up a folder for images on my storage drive, then again to view, drag and drop (copy) the images from memory card to that folder.
If the images on the memory card are JPEGs, they are directly viewable in Explorer (can display as thumbnail/icons in a couple sizes). But if they are RAW files (*.CR2, which are what I usually shoot), they can be moved or copied as simply labelled files, but the images themselves cannot be pre-viewed and will not show as a thumbnail/icon in Explorer. However, for 32 bit operating systems, Canon has a free Codex that can be downloaded and installed to allow CR2 to be viewed in Explorer. For 64 bit operating systems, the Canon codex won't work but there are third party Codex that are relatively inexpensive. I use one called FastPictureViewer, that cost me $15 per computer to install, and not only translates Canon RAW files, but also RAW from every major camera manufacturer and more. It works quickly and well, allows the RAW to be displayed larger in MS Picture Viewer too.
But the codex installation and viewiing images right in Explorer is completely optional. Once downloaded, you could simply point whatever software you normally use to work with your images to the folder you've created and placed the files in.
Another thing... if viewing the memory card in Explorer as a drive with folders, be sure to check if there are multiple folders on the card. After a certain number of images Canon cameras will set a second folder (and a third, fourth, etc.). It's possible the last photos you took were put into a different folder.
And, if you have previously viewed the memory card on your computer, now are looking at it again... depending upon how you are doing so, you might need to refresh the view to update and include the new images.
If you are using a Mac, it's a whole different world and I haven't used one in a decade or so, will leave it to others to advise about them. .
Aside from software-related problems, IMO the most common source of problems is card readers themselves and especially their connecting cables. If possible, try a second one. Or, connect the camera - with the memory card reinstalled - directly to the computer via the USB cable that came with it and see if the images can be found.
I was using my work computer that has Windows 7 on it. I was using Explorer to pull up the photos. They were small JPG files. I was being a good samaritan by taking photos of the kids and simply providing a 4x6 to the parents. After failing with the card reader, I did go home and insert it back into the camera and it said "no images." So I hooked up the camera to my home computer and ran a recovery program that scanned for several hours and could not recover anything. Oh, the sick feeling in my stomach is still there, and I suppose I will get over this soon. I just wish I knew what I did wrong. I did not format nor do a delete all. Thanks for your input, and Merry Christmas!
I wouldn't give up that easily. I'd recommend trying again using a card reader & not the camera & I'd try something well known as dependible such as the programs from Lexar, Sandisk or any other major card supplier. Most allow you to test snan & if the program finds the files you pay for the license to use the program & it then rescues your files AND you now have a dependible program ready for the next time it happens to you or someone you know.
Here's one I read about recently that did well.
Yes - 'reading' data does not degrade the life of flash memory in any way... you can read infinite times with no wear. It's only 'writing' that causes wear to a card.
Question: If you put the card in the camera and use the camera to review images, does the camera see those images?