By HERB A. LIGHTMAN A roving editor roves far afield to observe filming of the most popular world-wide stage musical of all time Zagreb, Yugoslavia It is early evening when the jet touches down at the Zagreb airport. Waiting for me is "FIDDLER ON THE ROOF" unit publicist Quinn Donoghue. My luggage is loaded into his car and he asks: "Do you want to check into your hotel first or go straight out to the location?" The company is on a night shooting schedule and has already been at it this evening for a couple of hours prior to my arrival. I don't want to miss a minute of it, so I tell him: "Let's go straight to the location. I can register at the hotel in the morning, when they've finished shooting." Then begins a drive of 30 miles or so through the Yugoslav countryside past neat farms and villages, heading toward the location where the most popular stage musical of all time is being painsĀ¬ takingly transferred to film by an expert and dedicated international crew. The genesis of my presence here was a casual remark made to me in London a few days ago by David Samuelson: "Why don't you pop over to Yugoslavia and have a look at what Ossie is doing with 'FIDDLER'? I'm told he's getting some extraordinary footage." (LEFT) The mythical village of Anatevka, as constructed on location in the countryside near Zagreb. (CENTER) Outside a Yugoslav cottage, used as exterior set and location Production Office, an actor is given a wardrobe fitting. (RIGHT) Camera rehearsal for a "magic hour" sequence in which the villagers leave their homes to attend a wedding ceremony.