So many cameras have this. I have had my Samsung GX10 (Pentax K10D) for about 12 years, and throughout this time the OPS always bothered me because it does not seem to do anything. When the switch points to "Off" nothing happens, so maybe that setting works. When the switch points to "On" the green shake-hand can sometimes illuminate in the viewfinder, so something works. However, whether OPS is on or off, I cannot feel a difference in my hand and all the photos I have ever tried to test this with look the same. Is there a test to verify OPS actually works?