Nikon D100 - Manual (Page 191)

Technical Notes—Optional Accessories
Lenses and Other Accessories
179
Calculating Picture Angle
The size of the area exposed by a 35-mm
camera is 24
×
36 mm. The size of the area
exposed by the D100, in contrast, is
15.6
×
23.7 mm. As a result, the picture
angle of photographs taken with the D100
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.
Picture size (D100)
Picture size (35-mm format)
Lens
Picture diagonal
Picture angle (35-mm format)
Picture angle (D100)
(24 mm
×
36 mm)
(15.6 mm
×
23.7 mm)
35-mm film camera
D100
85
127.5
17
25.5
20
30
24
36
28
42
35
52.5
50
75
60
90
35-mm film camera
D100
600
900
105
157.5
135
202.5
180
270
200
300
300
450
400
600
500
750
Picture angle
Approximate focal length (mm) in 35-mm format
(modified for picture angle)
Picture Angle and Focal Length
A 35-mm camera has a diagonal picture angle approximately one-and-a-half
times that of the D100. When calculating the focal length of the lenses for
the D100 in 35-mm format, you will therefore need to multiply the focal
length of the lens by 1.5, as shown in the following table: