The GN was interesting idea. It was made to use with a flash; you
enter the guide number (GN) on the side, lock the aperture ring
and then the aperture automatically adjusts to perfectly expose
your flash photos. Genius!
This is a non-AI version that has been retrofit for AI.
It is in excellent condition with light wear and works perfectly. The glass is clean and scratch-free with no haze, fungus, nor other issues. The focus and aperture are smooth.
The lens caps are included.
SKU: 250321-17