Nikon F3 - Manual (Page 29)

ASA film speed dial ®
The scale on the ASA dial has numbered settings for
speeds from ASA 12 to 6400. Two dots between each pair
of ASA numbers stand for intermediate settings, such as
64, 80, etc. The table below gives the speeds for all inter­
mediate settings.
12 25 50 100 200 400 800 1600 3200 6400
16 20 32 40 64 80 125 I 250 1 500 i lOOOl 2000l 4000(
160 320 640 1250 2500 5000
21
ASA is a numerical rating of the film's sensitivity to a
given amount of light. The higher the number, the
greater the sensitivity, and vice versa. The ASA of your
film is indicated on the cartridge itself. It is also printed
on the film carton and on the data sheet packed inside.