The diopters do not lock. They rotate just like the other models of geovids. They do seem looser than I would like and I can see myself turning them accidentally when turning up the eye cups if I’m not careful. I also noticed there is no SIM card on board and the display doesn’t show temp, pressure, and angle. I’m sure it’s taken into consideration for the calculation but not displayed. That’s a bummer because I enjoyed checking the temp when bored and freezing my butt off . These are the only negatives I have found so far.How are the diopters? In another post I heard they are non locking. How easily moved/knocked off?
Forgot to mention, the reading is almost instantaneous after pressing the button. For when micro seconds count