Each image may have a different credit (this is a historical image database). For the IPTCImageCredit field, one image has "Andrews University Public Relati", which should read "Andrews University Public Relations". For the IPTCSource, I have one that shows "http://www.centerforadventistres" which should read "http://www.centerforadventistresearch.org/gallery/photographs". I am not really worried about the IPTCSource field, as we probably won't use it in the display (since it's the same for each photograph, I will probably just write the credit notice into the image.php code). But since it was truncating too, I mentioned it.
Most EXIF fields in the database are setup with var(52) or even var(32) so anything with more chars is truncated then. I have to admit I don't know why they are so tight but I am rarely using EXIF data myself.
My colleague will have an idea. Maybe the char limit is part of the official exif specs then it would make sense.