@Harumaki_NA Some cameras allow the use of both, F3 included (albeit pre-AI lenses can't communicate the aperture so stop-down metering must be used)
Just remember to flip the lever/tab away
@Harumaki_NA Interestingly your lens is a pre-AI unit, but factory-converted (by Nikon) to be an AI lens
Left: Pre-AI
Right: AI-converted
There's also articles that explain it better:
https://t.co/742Z6sKYnI
https://t.co/ExeaUI8n5y
@Harumaki_NA Left: AI
Right: Pre-AI
Easiest way to tell apart is the AI lens have a notch in the mount, an aperture ring with two rows (with holes in the prong to allow you to see the selected aperture)
Pre-AI lenses doesn't have those
@Harumaki_NA Pre-1977 lenses require you to set the aperture of the lens to f/5.6, mount, rotate to the largest and lowest apertures to "calibrate" it (there is a prong on the lens)
1977 introduced AI (automatic indexing), which does away with that process, but with caveats