The shy professor of theology turned cardinal, chief inquisitor and keeper of the Catholic faith has shown the first glimpse of a mass communicator in the making - one whose DNA may not be infused with the star power of John Paul II but who has now, even if reluctantly, embraced the need to engage directly with his 1.2 billion global followers.

"It is in Sydney that this Pope has truly learnt his job," said Andreas Englisch yesterday. Englisch, a German author, journalist and member of the Vatican press corps since 1986, has written seven books, including two on Pope John Paul II and one on Benedict XVI.

"Ratzinger is a theologian. He knows his church but he knew it through books, through his writing, from his study but not from the people. In Australia, even more than in the United States, he has learnt the church from his people … they do not want to be kept at arm's length.

"In Cologne in 2006, 1.5 mill-ion people lined the Rhine to see him. He spoke only to the young people on the boat with him … there was no effort to wave, to smile, to acknowledge all those that came out to see him … There was much criticism of him, even from his bishops. Here in Sydney it has been different, completely different."

Pope Benedict, born and bred in the cold of Bavaria, seems to have thawed in Australia.

When he faced the first phalanx of television cameras and microphones on board the flight to Sydney from Rome seven days ago he looked transfixed, hesitant in demeanour and rusty in English, the language of his soon-to-be hosts in Australia.

"He was faced by a battery of cameras and lights … he is not at his best in a crowd, he looked like a deer caught in a spotlight," another veteran Vatican specialist on board the flight said.

"But just a few days later, if you talked to those 12 kids who had lunch with him at St Mary's, you would not know it was the same man," she said.

"He laughed, he relaxed, he played with the stress ball that one of the American kids gave him. Theatrics go against his nature, but he has learnt here to play his audience … even to punch his applause lines, to listen, to time delivery with them."

In the past seven days the Pope, a man of undisputed fierce intellect and steadfast theological position, has gradually allowed a different part of his personality to emerge. At last he has provided a glimpse of the man behind the mitre.

At Government House, during his first official outing after resting at Kenthurst, the Pope was led through a review of the troops - an Australian protocol for a visiting head of state but one that departed entirely with papal tradition. It was clear from the Pope's demeanour that he was unsure of what was expected of him - even mildly embarrassed - as the navy, army and air force military bands waited at attention and he was led past each one.

"It is simply not a papal thing to do … I think it has only ever happened once or twice, usually in small African nations," said a senior Vatican reporter and veteran of 19 papal trips.

"He is never made to walk past like that … but it was obviously local tradition, and so he stopped each time, he waved; he obviously seemed to want to make a human connection."

According to his spokesman, the Jesuit priest Padre Federico Lombardi, the previous pope, John Paul II, had come from a pastoral tradition. "All of us see the difference in their personalities, the difference in their approach to people. You only need to watch them to see that difference.

"I think that for John Paul II this [a World Youth Day event] was a very spontaneous thing. He also had a personal past in pastoral work with youth. He used to take canoe trips, nature walks in forests with them. His gestures, his ripostes to curious questions [from youth] were all spontaneous.

"Pope Benedict XVI was a university professor. You can see that too in the way he imparts his speeches, his relationships, the way he expresses himself and so on … he has a rapport with the young but is more shaped by his students. I think though that he has shown a great willingness to live this new pastoral experience, which he inherited from his predecessor but which he has now infused with his own characteristics, of simplicity, of humility and availability to all."

Padre Lombardi said what was most visible in Sydney was the Pope's direct participation with young people and that he allowed himself to become involved.

The changes observed in the Pope during his Australian trip are particularly significant as no cardinal of the Roman curia had ever enjoyed the celebrity status - but as an intellectual not a populist - enjoyed by Joseph Ratzinger in Europe when he was cardinal.

According to John Allen, the Pope's unauthorised biographer, the then Cardinal Ratzinger's fame "transcended the borders of church life; [making him] a bona fide public figure with a cultural profile similar to [the conservative commentator and writer] William F. Buckley jnr's in the United States."

In his biography, which the Vatican did not receive warmly as it meticulously and critically analyses Joseph Ratzinger's dramatic evolution from early libertarian theologian to arch-conservative, Allen points out that in German newspaper polls at the time he was cardinal, Ratzinger came in the top 30 of German's most important and powerful nationals. He was placed ahead of the then head of the German central bank and even the tennis player Steffi Graf.

Allen's final analysis rejects critics who portray the Pope as a man driven only by fear - of losing power, of women, of sex, of modernity. He argues that the very few people who know the man, and even those who disagree with his theological positions, describe him differently: "… He is a refined man with a lively sense of humour, not someone working out his personal pathologies through the power of his office," he writes. When asked once, on Bavarian television, what he was afraid of, Allen writes that his quick-witted response was "I'm afraid only of the dentist".

On Sydney Harbour, during a welcome usually afforded rock stars, the Pope surprised many when he moved out of the papal entourage and ensconced himself at the front of the boat, looking as excited as the teenagers who flocked around him.

Similarly, his triumphant tournee around the racecourse at Randwick yesterday was markedly populist and warm. His security men turned a blind eye to the many babies and toddlers thrust through the open window for the Pope to kiss.

The only real criticism of the week revolved around the complexity of his homily at the Saturday night vigil on the St Augustine's theology of the Holy Spirit.

Some youngsters found the teachings impenetrable, and even Padre Lombardi, in a flash of great humour, admitted that he and others who had read the homily found it difficult "on first impression".

But that, he said, was a good measure of this Pope. "It was his choice, to choose issues that invite reflection, that require work to understand, that may need you to come back and return to them to seek clarity. There are other things that he might have said that might glean greater applause … but they would not have stimulated thought."