This game uses the medium to long range scopes with 2D view while aiming down sight. As this game uses the ArmA III engine, and that game uses the 3D view for this kind of scopes, don't know why it is this way here in the Standalone. It gives a "cheap" game look to this awesome game, and i think it could be changed with no much effort, and it would give this game an awesome realistic look to the scopes.
Here i post how a long range scope looks in ArmA III, concretely the SOS scope.
And this is how the "Long Range Scope" Looks in DayZ SA
This is how the PSO-1 looks in DayZ SA
This is how the PSO looks mounted on a SVD rifle in real life.
And this is how a G7 long range scope looks in real life.