The F1N has a hybrid shutter that needs batteries for the slow speeds (I think), and it works without batteres (with stiffer shutter release button) for the rest of the speeds. Usually, only when the battery dies, remove the battery and then half the speeds will work.
Add a motor drive or winder, and the F1N has shutter priority.
Add the AE finder, and the F1N has aperture priority.
The standard FN finder when set to A gives you shutter priority without any read out.