I took snap shots of all the available cameras when 2.7W lock and 4W lock to see any scattering light change.
Only IFI and MCO cameras showed obvious differences depending on the power change. See the attached pictures. Left and right panels are when 4W and 2.7W, respectively. The IFI camera mainly shows the high power beam dump in the view. The left area of the dump is illuminated stronger when 4W. They may be some parts of IFI scattering the IR lights. The MCO camera shows the MCO mirror at the center and an oplev folding mirror behind the MCO mirror. The left column of MCO suspension is illuminated much stronger when 4W.
They must have very high scattered lights.
The snap shots are tiff files and can be numerically analysed furtuer. Any volunteers?
Snapshots are in
/kagra/camera/images/2.7W/
/kagra/camera/images/4W/
Script to take snap shots of all the cameras
/users/kokeyama/scripts/camera/snap_all_camera.py