Nikon FG-20 - What is AI?

WHAT IS AI?
The Nikon FG-20 is an AI-type (Automatic Maxi-
mum Aperture Indexing) camera which performs
full-aperture metering with
AI -type lenses such as
AI-S Nikkor, AI-Nikkor, and Series E lenses.
All AI-S and AI-Nikkor lenses can be identified by
a meter coupling ridge
@ and a meter coupling
shoe
® with two holes in it (see illustration). In
addition, the AI -S or AI symbol appears on the front
cover on the instruction manual for each lens.
Nikon Series E lenses also have the same features
as AI-Nikkor and AI-S Nikkor lenses, except they
do not have a meter coupling shoe.
AI-Type Lens
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