Nikon AI-S Micro-NIKKOR 105mm f-2.8 - Manual (Page 15)

Focusing on predetermined reproduction ratio
The reproduction ratio is, numerically, the relation­
ship between the image size (to be recorded on the
film) and the actual subject size. For example, if the
image on the focusing screen is one-fifth the actual
subject size, the reproduction ratio is 1:5.
Two reproduction scales are inscribed in orange
above the distance scale on the focusing ring. The
inner scale, with figures from 1:10 to 2, represents
reproduction ratios obtained when the lens is used
alone. The outer scale figures (from 2 to 0.88) repre­
sent possible ratios when the lens and PN-11 ring are
used together. Using either of these scales, you can
photograph at a predetermined ratio without calcu­
lating distances. For example, to photograph at a
reproduction ratio of 1:5, just turn the focusing ring
until the number “5” is aligned with the distance
index line; then aim at the subject and adjust your
position (closer to, or farther away from the subject)