Windows 7: how to revert nfts back to fat

i had a terrible problem with a big quantity of extremely important photo files; i formatted a pen drive by error and now i cannot access my photos; the card in the camera card filed as fat; my computer only files in nfts; a window popped up telling i had to format; i didnt realized the risk and formatted; now i cannot open the files because for sure they now are nfts; how could i revert the mistake i did?, there should be a way of reverting from nfts to fat, isnt it?; pls help me; i must find a solution!

I used to use a program called partition magic which would revert the change but the "INFO" would be gone but "YOU CAN RECOVER THE INFORMATION" by using recovery software like recuva from here: Recuva - Undelete, Unerase, File and Disk Recovery - Free Download

This would be the better choice and it's free: http://www.partitionwizard.com/

Whatever you do do not try and reformat that pen drive until running Recuva on it, or they will be gone for good.

Correct do not format...

The files aren't gone because the format is now NTFS, they are gone because the device was formated. Formating erases the contents of the device thats being formated. You may be able to recover the data, but I wouldn't hold my breath. Windows can handle fat and NTFS formats no problem. A camera or other similar device may not be able to handle NTFS though. If it used a custom format that windows can't handle, that may be why you were prompted to format. If an SD card or USB thumb drive gets corrupted, it can cause you to get the prompt to format the device.