Iris and Exposure
You can manually adjust the iris/exposure for the camera, which sets the aperture for the amount of light that hits the camera lens (measured in F stops).
To manually adjust the iris, on the back left of the camera, set the AUTO/MAN switch to MAN for manual.
Then on the top middle of the camera push the IRIS button.
Then on the left front of the camera set the ZOOM/FOCUS/IRIS switch to IRIS.
You now can turn the manual ring to adjust the iris.
When the camera is set to manual iris, on the LCD screen will appear F stop values for the iris settings.
When in manual mode, if you want to quickly have the camera adjust the iris to the correct exposure for you, press the iris button on the right of the camera. You can still manually adjust the iris from this point on, but pressing this button will temporarily set the iris to the correct exposure for the current scene in the viewfinder.
To return to automatic iris, push the IRIS button again (the F stop values will disappear from the LCD screen).