Nikon Z 6II Reference Manual page 161

D
High ISO Sensitivities
The higher the ISO sensitivity, the less light needed to make an exposure,
allowing pictures to be taken when lighting is poor and helping prevent
blur when the subject is in motion. Note, however, that the higher the
sensitivity, the more likely the image is to be affected by "noise" in the
form of randomly-spaced bright pixels, fog, or lines.
D
Hi 0.3–Hi 2.0
A setting of [Hi 0.3] corresponds to an ISO sensitivity approximately
0.3 EV higher than the camera's highest numeric ISO value (25600 in the
case of the Z 7II, 51200 in the case of the Z 6II), equivalent to ISO 32000 in
the case of the Z 7II or ISO 64000 in the case of the Z 6II. [Hi 2.0]
corresponds to an ISO sensitivity approximately 2 EV higher (102400 in
the case of the Z 7II, 204800 in the case of the Z 6II). Note that pictures
taken at these settings are particularly prone to "noise" in the form of
randomly-spaced bright pixels, fog, or lines.
D
Lo 0.3–Lo 1.0
[Lo 0.3] corresponds to an ISO sensitivity about 0.3 EV below the camera's
lowest numeric ISO value (64 in the case of the Z 7II, 100 in the case of the
Z 6II), equivalent to ISO 50 in the case of the Z 7II or ISO 80 in the case of
the Z 6II. [Lo 1.0] is roughly 1 EV below the lowest numeric ISO value,
equivalent to ISO 32 in the case of the Z 7II or ISO 50 in the case of the
Z 6II. Use for larger apertures or slower shutter speeds when lighting is
bright. Highlights may be overexposed. In most cases, ISO sensitivities of
ISO [64] (Z 7II) or [100] (Z 6II) or above are recommended.
The S Button
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