Nikon P-400R Instructions Manual page 73

About Program AE settings
In Program AE mode, the upper limit on the camera gain and the lower limit on
the slow shutter speed can be set. By specifying these settings, the user can
determine the balance between prevention of vibration due to a slow shutter
speed and avoidance of image quality degradation (increase of image noise) due
to a high camera gain.
If prevention of vibration is more important, set the lower limit on the slow shutter
speed to a fast speed (1/60 sec. or faster), and set the upper limit on the camera
gain to the maximum. These settings avoid using a slow shutter speed if at all
possible.
If avoidance of image quality degradation is more important, set the lower limit on
the slow shutter speed to a slower speed to minimize increase of the camera
gain. Note that if the upper limit on the camera gain is set low, the range in which
the correct exposure is obtained is narrow if the brightness of the object is low.
The camera gain is set to the
upper limit and the shutter
speed is set to a slower
speed than the lower limit to
obtain the correct exposure.
Underexposure
1/1000
1/60
1"
2250
100
Low
Relationship between the camera gain and shutter speed
(when the upper limit on the camera gain is 2250 and the lower limit
Exposure control in Program AE mode
If the brightness of the object is high, the P-400R first decreases the camera gain
to maintain the image quality, and then increases the shutter speed to obtain the
correct exposure.
If the brightness of the object is low, the P-400R sets the shutter speed to the
lower limit, and adjusts the camera gain to obtain the correct exposure. If the
object is underexposed even when the camera gain is set to the upper limit, a
shutter speed slower than the lower limit is used. The camera gain never
exceeds the upper limit.
P-400R Digital Microscope Instructions
Camera gain
Object brightness
on the slow shutter speed is 1/60)
57
The shutter speed is set to the lower
limit. The camera gain varies to obtain
the correct exposure.
The camera gain is set to the
lower limit. The shutter
speed varies to obtain the
correct exposure.
Shutter speed
High
Overexposure
5