Yes, it is OK to supply multiple servos from the same power source. That power source should have capacity for both servos.
But if the motors burnt out in the servos, that is not a power supply problem.
Did you stall the motors and leave them stalled? As in, command the servo to move to a position, but put a load that the servo cannot move on the servo output. This will burn out any servo.
How much physical force does it take to move the lens and adapter? Are there any hard stops that your servos might be trying to run past?