Nikon D2H manual Picture Angle and Focal Length, 230, Technical Notes-Optional Accessories

Technical Notes—Optional Accessories

CPU lenses can be identified 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 lenses, 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

A 35-mm camera has a diagonal picture angle approximately one-and-a- half times that of the D2H. When calculating the focal length of the lenses for the D2H 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:

			Approximate focal length (mm) in 35-mm format
	Picture angle			(modified for picture angle)
35-mm film camera		17	20	24	28	35	50	60	85
	D2H	25.5	30	36	42	52.5	75	90	127.5
35-mm film camera		105	135	180	200	300	400	500	600
	D2H	157.5	202.5	270	300	450	600	750	900

Calculating 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 D2H, in contrast,	Lens
is 23.3 ×15.5 mm. As a result, the picture
angle of photographs taken with the D2H
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 (35-mm format) (36 mm ⋅ 24 mm)

Picture diagonal

Picture size (D2H) (23.3 mm ⋅ 15.5 mm)

Picture angle (35-mm format)

Picture angle (D2H)

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