Nikon D70s Manual page 195

Picture Angle and Focal Length
A 35-mm cam era has a di ag o nal pic ture angle ap prox i mate ly one-and-a-half
times that of the D70S. When cal cu lat ing the focal length of lenses for the
D70S in 35-mm format, you will therefore need to mul ti ply the focal length
of the lens by 1.5, as shown in the following table:
Picture angle
35-mm fi lm camera
D70S
35-mm fi lm camera
D70S
Cal cu lat ing Picture Angle
The size of the area exposed by a 35-mm
camera is 36 × 24 mm. The size of the
area exposed by the D70S, in contrast,
is 23.7 ×15.6 mm. As a result, the picture
angle of photographs taken with the
D70S differs from the picture angle for
35-mm cameras, even when the focal
length of the lens and the distance to the
subject are the same.
Approximate focal length (mm) in 35-mm format
(modifi ed for picture angle)
17 20 24
25.5 30 36
105 135 180
157.5 202.5 270
28 35
42 52.5
200 300
300 450
Lens
Picture angle (35-mm format)
50 60 85
75 90 127.5
400 500 600
600 750 900
Picture size (35-mm format)
(36 mm × 24 mm)
Picture diagonal
Picture size (D70S)
(23.7 mm × 15.6 mm)
Picture angle (D70S)
185