The Canon new F1's multiple exposure modes, wide range of accessories and compatibility with a large range of lenses make it a very versatile camera for the serious photographer. In it's most basic form, the camera offers match-needle manual metering and stopped down metering. With the AE Motor Drive or the AE Power Winder attached, shutter priority automatic exposure is possible. The AE finder, fitted to most examples provides a display of the shutter speed when in aperture priority or stopped down AE mode. But the camera can actually be used in these modes without the AE finder, because the necessary electronics are built into the camera body, not the finder. In practice, the manual metering mode is so good that there is little need to use anything else most of the time.
the Speed Finder FN is a useful accessory which features a rotating eyepiece, allowing the viewfinder image to be viewed at eye level or from above, or from one side. This finder also provides sufficient eye relief to allow use with goggles or a crash helmet.
The most useful of the interchangeable focusing screens for general photography are probably the bright laser matte, types J (lenses up to 300mm) and K (lenses of 300mm focal length and over). The type K provides an extremely bright viewfinder image even with small aperture telephoto lenses, and is also very useable with standard and wide angle lenses although the type J is optimised for these lenses.
If you want a cheap leather case for this camera, the case for the old Chinon CS/CX cameras will fit the F1N with eye level finder perfectly. The bottom part of the case only can be fitted to the F1N with the AE finder attached.
Many of the secondhand cameras offered for sale have a dented prism housing. DIY repair of the AE finder involves removing the mask inside the eyepiece (loosen the glue with solvent first), removing the screws underneath together with the screw holding on the eyepiece shutter operating lever and all other screws in the housing cover, lifting off the cover, beating out the dents, glueing the transparent window and mirror back into place and then re-assembling.