The N80 and N80 QD are different in terms of how they operate. The N80 QD can imprint the date that the photo was taken unto the negative, and the N80 is not capable of imprinting the film's data; you must depend on your memory of when you took that picture, which can be a big problem if you are someone who takes a lot of pictures.
N80 QD can even put the date imprint on or off, considering your preference, and with this feature turned off, the N80 QD is a step above N80. Otherwise, they are the same as one another. QD can do what N80 can do and then some.
Nikon is a popular brand of cameras. N80 vs N80 QD are SLR cameras, which used film. They came before the realm of digital cameras that are widely used today. These cameras are identical to each other, even with having the similar name.
The only difference between them is that the QD is able to print a date on the film. This is important for those who needed to remember a special date that photos were taken or wanted to keep track of how many photos they may have taken on a certain date. If a person did not need this feature, they could stick with the N80