Adding EXIF data-Is it possible with any software/freeware?

[gendarmee]

I would like to add EXIF, such as camera name and date, to Scans/HDR images, is it possible to do that using any software?

 

[Mav]

I just Googled for EXIF editor and it looks like there's a bunch of stuff that will do it, although I have no clue what's good. I've heard of Opanda and know that's pretty decent, but it's Windows only and I'm a Mac guy.