On the New F1 in Manual and Stop Down Manual modes the lens can not be set on A and the shutter dial cannot be set on A . Any type of finder can be used and the use of a motor drive is optional. For Aperture Priority AE and Stopped-Down AE modes the lens can not be set on A. The shutter speed dial is to be set on A. The AE Finder FN must be used and the motor drive is optional. For Shutter-Priority AE and Electronic Flash AE modes the lens is set on A and the shutter dial can be set to any speed. For Electronic Flash AE mode the shutter cannot be set on B. Any type of finder can be used and the use of a motor drive is required.
Setting the Aperture ring and Shutter Speed dial both to A (with any type of finder installed) at the same time will cause the aperture to close to its smallest value and the camera will then set the shutter speed automatically to give the correct exposure if possible. This can result in long or wrong exposures.