Four Sons, from 1928, is one of the greatest works of German expressionist cinema -- even though it was made by the Irish-American John Ford in Hollywood, U. S. A. Ford doesn't just seem to be working under the influence of Murnau here -- he seems to be channeling Murnau. If the film had somehow been misattributed to Murnau, it would be very difficult to correct the mistake by means of a stylistic analysis. Ford even, at one point, seems to be following in Murnau's missteps -- Four Sons, like The Last Laugh, has an odd extended epilogue which violates the tone of the rest of the film but somehow seems to work in spite of that, lightening the mood in a strange, surreal way without diminishing the power of the work as a whole.
In Four Sons Ford moves his camera as elegantly and expressively as any director ever has -- and the plastic invention involved is ravishing. The lighting is typical of Murnau, employing soft, glowing, complex chiaroscuro effects as opposed to the stark contrast of light and shadow often associated with expressionist cinema (and which Ford himself came to favor in his later "expressionist" films, from The Informer to The Fugitive.)
Ford had two great masters in his formative years, first Griffith and then Murnau. What's astonishing is how totally he was able to absorb each man's style -- he didn't seem to be imitating it so much as working within it naturally and unselfconsciously. Maybe even more astonishing is that Ford absorbed Murnau so quickly. We know how powerfully Sunrise affected him -- just from viewing the rushes he declared it the greatest film ever made. Less than a year later he was working with full confidence and mastery in the Murnau style -- and even shot parts of Four Sons on sets from Sunrise that were still standing.
Apart from its lack of a strong female lead, Ford's Just Pals could have been directed by Griffith and would rank among Griffith's more enjoyable minor films. The epic visual poetry of Ford's The Iron Horse bears favorable comparison with the epic visual poetry of The Birth Of A Nation -- which is saying a lot. If Four Sons had been directed by Murnau, it would rank among the German director's most important works -- and that may be saying even more.