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Technical Notes—Optional Accessories
CPU lenses can be iden ti fi ed by the presence of CPU contacts. Type G lenses are
marked with a “G” on the lens barrel, type D lenses with a “D.”
CPU lens Type G lens Type D lens
Type G lenses are not equipped with a lens aperture ring. Unlike other CPU lens-
es, there is no need to lock the aperture ring at the minimum aperture setting
(maximum f/-number) when using a type G lens.
Picture Angle and Focal Length
The diagonal picture angle of the D200 is less than that of a 35-mm cam era.
When cal cu lat ing the focal length of the lenses for the D200 in 35-mm format,
mul ti ply the focal length of the lens by about 1.5:
Option Approximate focal length (mm) in 35-mm format (modifi ed for picture angle)
35-mm camera 17 20 24 28 35 50 60 85
D200 25.5 30 36 42 52.5 75 90 127.5
35-mm camera 105 135 180 200 300 400 500 600
D200 157.5 202.5 270 300 450 600 750 900
The size of the area exposed by a 35-mm
camera is 36 × 24 mm. The size of the
area exposed by the D200, in contrast,
is 23.6 ×15.8 mm, meaning that the diago-
nal picture angle of a 35-mm camera is ap-
proximately 1.5 times that of the D200.
Cal cu lat ing Picture Angle
Picture size (D200)
Picture size (35-mm format)
Lens
(23.6 mm × 15.8 mm)
Picture diagonal
(36 mm × 24 mm)
Picture angle (35-mm format)
Picture angle (D200)
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