I think diving should reduce your stamina, since diving onto your chest and elbows is going to hurt alot.
A alternative would be dropping into a roll on your side by holding the prone key, the longer you hold the prone key the longer you'll roll, you could bring your back upwards and aim quicky by pressing the iron sights key, this would bring you into cover like craters about as fast as diving and take up less stamina but wouldn't bring you over short objects.
Taking up the least stamina would be dropping onto your knees, then your elbow, then into the proper prone stance.
A alternative would be dropping into a roll on your side by holding the prone key, the longer you hold the prone key the longer you'll roll, you could bring your back upwards and aim quicky by pressing the iron sights key, this would bring you into cover like craters about as fast as diving and take up less stamina but wouldn't bring you over short objects.
Taking up the least stamina would be dropping onto your knees, then your elbow, then into the proper prone stance.