“Bless thee, Bottom, bless thee! Thou art translated,” marvels Quince on seeing his friend turned into an ass. Whether it's Bottom's physique, the lovers' relationships or Oberon's violent mood swings, A Midsummer Night's Dream places “transformation” under the literary microscope, a theme that has beguiled writers dating back to classical antiquity. Shakespeare draws much of his material from Ovid's Metamorphoses, with the mechanicals' interpretation of the Pyramus and Thisbe tale and Helena's reference to Daphne in pursuit of Apollo being just two examples. In a study of shifting form, tonight's dedication to the Bard paired Mendelssohn's incidental music with another work inspired by The Metamorphoses: Matthias Pintscher's mesmerising Reflections on Narcissus. Pintscher himself conducted, and, though the drama ranged from the magical to the mundane, it was he that emerged as the star of the evening.

Pintscher has long been considered a composer of class, but has come to prominence as a conductor only more recently. He also possesses clear flair for programming, with the glistening surfaces of Reflections on Narcissus proving an ideal aperitif to Mendelssohn's fairy music in particular. The work's five movements flow into an unbroken whole and pitch what the composer refers to as an “insanely inflamed” cello part (here played by Alisa Weilerstein) against a warping meld of exotic timbres. This is music that dodges the cosy confines of a given programme, evoking instead the essence of water in movement and Narcissus' transforming emotional states.

There was impressive co-ordination from all involved. Weilerstein looked the part in blood-red dress – perhaps a reference to the white mulberry Narcissus stains when wounded – and was a picture of fearsome determination as she kneaded vibrant colour into the outer extremities of her range. Pintscher, in contrast, was a cool customer with a glint in his eye, at times sinking into the balustrade, eliciting orchestral outbursts with fingers cocked like a pistol. The BBC Scottish Symphony Orchestra's Artist-in-Association since 2011, Pintscher clearly knows how to coax fine playing from this band. Players pounced on his gestures like panthers on morsels.

As the dramatic forces multiplied the dramatic impact weakened. Mendelssohn's incidental music for A Midsummer Night's Dream, for which he sourced material from his earlier Overture, was commissioned by King Frederick Wilhelm IV of Prussia as an accompaniment to performances of the play. This was just one of a number of recent outings the work with textual fragments included, in which Gerard McBurney's much-shortened 2011 adaptation provided useful dramatic signposts and allowed us to enjoy Mendelssohn's melodramas with a sense of how they were originally conceived.

This was in many respects a dynamic semi-staging, Simon Manyonda's Puck on particularly impish form as he fizzed through clusters of Prommers. But static deliveries from the actors robbed the text of enchantment – there were hints of under-preparation with actors preforming on-copy - and lovers' contributions were flat, the comedy rough and ready. Only Mark Benton's Bottom reacted discernibly to musical cues, rejected by Titania and shuffling offstage to genuine titters. The Finchley Children's Music Group showed us just how bright-eyed singing is done, and did so with nary a score in sight.

We were treated to an uncut version of the score featuring all of the numbers, here invested with all of the finesse of the earlier Pintscher from pattering fairy feet in the Overture to a smouldering account of the “Nocturne”. “You spotted snakes” was a highlight – Katharine Broderick and Clara Mouriz provided a sinuous duet – but it was Pintscher who plastered a smile on our faces, leaning from his podium to punctuate the mechanicals' scenes with physical quips.

“Think but this, and all is mended, that you have but slumber'd here”, implores Puck in his final lines. We may have been short-changed of transformative magic, but there was enough musical brilliance to keep us from dozing.