The Santa Fe Opera has, over the course of its 28-year history, become the foremost summer operatic institution in America. The young talent that has gotten a start here, the administrators that have gone off to join or even form other important regional companies, and the depth of choice of repertoire - these aspects have served to keep the institution vital.
But it's always been a source of mystery that John Crosby, the opera's founder and so often astute general director, has never seemed able to differentiate between good and bad productions in the making. His choice of repertoire over the years has been imaginative and varied, with an amazing list of United States and world premieres and an often imaginative relook at old chestnuts. But too often, important premieres, or even simple works, are given substandard productions.
In the matter of repertoire, this season is the most rarefied of the five I have attended. The major crowd-getter is Mozart's ''The Magic Flute,'' hardly an opera with the same popularity as, say, Puccini's ''La Boheme,'' or even Mozart's ''The Marriage of Figaro.'' The other two operas seen at this writing include Cimarosa's ''Il Matrimonio Segreto'' (''The Secret Marriage'') and a double bill of Zemlinsky's ''Eine Florentinische Tragodie'' (''A Florentine Tragedy'') and Korngold's ''Violanta.'' Still to come are Henze's ''We Come to the River'' and Strauss's ''Intermezzo.''
This problem of not controlling productions before they go awry made the Zemlinsky opera - being given its US professional premiere here - unpalatable in the extreme. Among other claims to musical fame, Zemlinsky taught the young Arnold Schoenberg. Of late, this utterly forgotten composer has been the subject of a major revival: This one-act Oscar Wilde-inspired shocker is perhaps the best crafted of his major works to be heard so far. Director Bliss Hebert, who is so often afflicted by severe lapses in taste, here threw caution to the winds and turned a smoldering, brooding drama into a crude, smutty hour culminating in a gratuitous, indefensible nude scene. And yet, two seasons back, Mr. Hebert staged a delectable - if slightly overbusy - ''Mignon'' that was a model of fine opera staging. But so overbearingly obnoxious was this production of the Zemlinsky that one could be easily led to believe the work was worthless.
In truth, it is a richly textured opera: Zemlinsky deftly sustains, through orchestral timbres, sonic fabric, and the use of melodic flashes, the oppressive , decadent mood of the drama. And one might also have tended to overlook the excellence of Edward Crafts's Simone, though he was overparted by the role and overpowered by Mr. Crosby's harsh, unpliant conducting.
Korngold, who studied under Zemlinsky, wrote ''Violanta'' at the age of 17. He would later write another opera, ''Die Tote Stadt (''The Dead State''). Still later he would emigrate to America and become the film-music composer for Errol Flynn's greatest adventure movies.
''Violanta'' is a remarkable achievement for a composer of any age. That a 17 -year-old could write with such authority for an orchestra, could evince such a keen yet sensitive dramatic sensibility, and could serve up major roles of such vocal/theatrical impact invited the use of the word genius when the opera had its world premiere in 1916.
Mr. Hebert tampered far less with this piece. In fact, on Nancy Thun's heavy, unattractive blue set (abetted by Craig Miller's peculiar, pulsating lighting), action too often came to a standstill. In soprano Mary Jane Johnson, Mr. Crosby had a Violanta of majestic bearing. The role requires a weightier voice than she possesses. Nevertheless, she had no troubles fitting her securely used soprano to the terrifying heights and depths of the vocal line. Neil Rosenshein made a dashing Alfonso, singing with an unaccustomed bite and gleam in the upper reaches, though with a touch of commensurate (and potentially alarming) tension. Carolyn James and William Dooley made much of lesser roles.
In music that should caress and bewitch, Mr. Crosby tended rather to hector and overplay. Both works were sung in German, to an audience that had little idea of what was going on. Nevertheless, it was clear that both these works have the potential of holding a stage grippingly; both deserve wider circulation.
One has come to expect at least one production at Santa Fe to be garish and still another to be a grinding failure. This season, the ''Magic Flute'' was that stultifying flop, from design (Steven Rubin), through direction (Robin Thompson), down to conducting (George Manahan). It all looked and sounded like a music academy's careless first crack at Mozart's sublime work. Even such fine singers as Stephen Dickson (Papageno) and Sheri Greenawald (Pamina) were so poorly directed as to make them appear unseasoned and uninterested.
Yet, when one encounters a vintage Santa Fe night, one sees just how excellent this company can really be. Veteran Italian baritone Renato Capecchi was invited to stage the Cimarosa ''Secret Marriage.'' The cast worked together as an ensemble wherein everyone shone, vocally and histrionically. Judith Christin's riotous Fidalma and Claude Corbeil's stuffy-pompous-vacuous Count Robinson were particularly enjoyable.
Mr. Cappechi - who also sang Geronimo - knows the style of this cherishable little opera thoroughly. Nowhere was there anything cheaply slapstick or gratuitously laugh-grabbing. Each singer presented a fully polished character. The action meshed into a lovely entity. Kenneth Montgomery's conducting was gracious, graceful, and attentive to singers in matters of tempo, phrasing, and dynamic. Whereas a performance in English would have won more friends for this curiously little-known work, it remained from beginning to end just the sort of show one expects to encounter - and should be encountering - regularly at Santa Fe.
Performances of all three works run through Aug. 25 at the open-air opera house, one of the all-time extraordinary settings for opera in this country.