Perhaps it is; Brown's book had the same fault. And Akiva Goldman's screenplay, like Brown's writing, is not of the kind to inspire actors.
Which makes McKellen's tetchy, watchable efforts the more commendable.
He is almost matched by Paul Bettany as Silas, the mad and deadly monk, and by Jean Reno, as the French policeman with a few unorthodox strings to his bow.
In the main, though, the film either plods faithfully along or indulges in spurts of melodrama that even a saint might find incredible.
It seems to hang like a limpet on the weight of the book, without finding a style to suit itself.
It was made on a whopping £67 million budget but no matter how much you spend on a movie, you can't create really good cinema that way.
It may well be enough for those who adore the book - and for those who actually believe it.
But, as a piece of cinema, this film has a good many limitations. These do not include Hans Zimmer's score, the scary nature of which apparently had to be scaled down to satisfy the censor that the movie could receive a 12 rather than 15 certificate.
Though it starts with a grizzly murder and continues with Silas flogging himself painfully towards a proper appreciation of Christ's suffering, The Da Vinci Code won't sit comfortably within the market designed to scare.
It is, as they say, a thriller, with mystical intimations. And, as such, I'd take a bet that it will suit the public better than us pesky critics.
