IL3 User’s Guide
page 26
11S-3002B
4-2 Setting Shutter Speed
The Shutter Speed is expressed in microseconds of exposure time.
Minimum Exposure:
Minimum exposure is 2
m
sec (regardless of frame rate)
Maximum Exposure:
The maximum exposure time is dependent on the frame rate. It is always
(1/Frame Rate) - 6
m
sec
For example, at 500 fps, the maximum exposure is:
(1/500 sec) -6
m
sec
= 2000
m
sec -6
m
sec
= 1994
m
sec
For those accustomed to using shutter angle, to convert that to degrees:
(Exposure (in
m
sec) / Frame Time) X 360
o
For example, at 500fps, an exposure time of 250
m
sec is:
(
250
m
sec / 1/500 sec) X 360
o
= (250 / 2000) X 360
o
= 45
o
Setting the Shutter Speed
:
Shutter Speed is set using the slider or edit box in the “Shutter Settings” section of the Record Settings
Tab. (See “Figure 4-2: Shutter Settings”.)
Low Light Mode:
In some special circumstances, the light available for setting up the IL3 for a high-speed event is not as
bright as what will be used for event itself. You may, for example be using some lights that can only be
switched on for a short time and are not available for camera set up.
The exposure for Low Light Mode is much longer than would be possible for a high frame rate. The
default shutter speed for Low Light mode is 33.327ms, which is the “1X” shutter speed for 30 FPS. The
shutter speed for Low Light may be adjusted via Fas
M
otion by checking the Low Light box and moving
the slider or editing the Low Light edit box.
To enter Low Light Mode:
Note:
Be careful when using the Low Light feature!
It is very easy to forget that it is on!
Remember to
set your exposure for the light that will be present during the image capture.
1. Set the Shutter Speed just as you need it for the
high speed event.
2. Click on the Low Light check box. A check mark will
appear in the box. The edit box and the slider will
become active.
3. Adjust the slider or edit the box for the desired
exposure.
4. Press the Arm Button.
The camera will begin recording. You will notice that the image is darker now than in Live Mode.
5. Press Arm again to quit recording. (Click “OK” on the Warning message to Cancel.)
Figure 4-2:
Shutter Settings
