Photron Fastcam SA3, Hardware Manual

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27 FASTCAM SA3 Hardware Manual

When the auto exposure function is operating, the camera will not perform a shutter operation with
an exposure time longer than the shutter value set here.
These settings are shown in the diagram below.
If the image level being output (the average value of the area set with AREA) is
①
,
②
, or
③
, the
function operates as below.
For position
①
Since the image level being output is higher than the range TARGET VALUE±RANGE, the function
operates to close the shutter (shorten the exposure time).
If position ②
The image level being output is lower than the range TARGET_VALUE±RANGE , so the function
operates to open the shutter (lengthen the exposure time).
If position
③
The image level being output is within the range of TARGET_VALUE±RANGE , so the operation of the
shutter is not varied.

The DS SHUTTER function is inactive while the AUTO EXPOSURE function is being used.
 When the RANGE setting is a small value, the range of the desired image output level narrows.
 If the RANGE value is made smaller than necessary, the image level is difficult to place in the
desired
③
position.
In this case, the variable shutter operation cannot place the image level in the desired
③
position
and a phenomenon occurs where the image output level is unstable.
When a situation like this occurs, it can be resolved by making RANGE a larger value.
③
③
①
②
+ RANGE
TARGET VALUE
- RANGE