Nikon f2 - Manual (Page 28)

FOCUSING—continued
Infrared Photography
The plane of sharpest focus for infrared light is slightly
more distant than its counterpart for visible light as seen
through the camera’s viewfinder. Thus, for sharpest
focus in infrared photography, adjustments must be
made.
To compensate for this shift in focus, first focus the im­
age sharply through the viewfinder. Then, turn the fo­
cusing ring counterclockwise until the point focused is
aligned with the red dot (or line) provided on the lens
barrel. For example, in the picture below, the lens has
been focused for infinity (°°) infrared shooting. Note
that when lenses having a focal length of 50mm or less
are used stopped down to f/8 or below, no adjustment is
necessary due to the large depth of field available.
Note: Some new optics using Nikon's Extra-iow Dispersion
(ED) glass, as well as reflex (catadioptric) lenses, do not require
refocusing for infrared photography. Refer to individual lens
instruction manuals for details.
18
Film-Plane Indicator
Under various precision shooting situations, such as
close-up photography, it is often necessary to measure
the film-to-subject distance to ensure the sharpest focus.
The camera’s film plane is indicated by the top edge of
the figures making up the serial number at the upper
left of the camera body. Note that these figures are
46.5mm from the front surface of the camera’s lens
mounting flange.
(mounting flange front surface)