Nikon D90 user manual Compatible Lenses, 228, Calculating Picture Angle, Lens f-number

Compatible Lenses

CPU lenses (particularly types G and D) are recommended for use with the D90. CPU lenses can be identified by the presence of CPU contacts, type G and D lenses by a letter on the lens barrel. Type G lenses are not equipped with a lens aperture ring.

CPU contacts Aperture ring

CPU lens Type G lens Type D lens

ACalculating Picture Angle

The size of the area exposed by a 35mm camera is 36 × 24 mm. The size of the area exposed by the D90, in contrast, is 23.6 × 15.8 mm, meaning that the picture angle of a 35mm camera is approximately 1.5 times that of the D90. The approximate focal length of lenses for the D90 in 35mm format can be calculated by multiplying the focal length of the lens by about 1.5.

n

Picture size (35mm format) (36 × 24 mm)

Lens Picture diagonal

Picture size (D90) (23.6 × 15.8 mm)

Picture angle (35mm format)

Picture angle (D90)

ALens f-number

The f-number given in lens names is the maximum aperture of the lens.

228