I use 18-140 Nikkor . This lens have two A & M focus mode and this lens is AF-S that mean when auto focus is enable the focus ring dose't move. If i do manual focus when the lens is at A mode , does it harm the lens ? or its safe.
In general, you can damage your lens if you turn the focus ring while in autofocus mode. The exception is ring-type lens motors (often branded "ultrasonic" or similar), or some Pentax lenses which have a clutch mechanism.