Vladislav Steinberg, St John's Smith Square, London

Paganini's 24 caprices are the violinist's Everest. Brave players, usually bravura specialists, may offer a selection, but hardly any risk their reputations with the complete set. It was claimed that Vladislav Steinberg's performance on Saturday was the first in London, at least since Paganini himself played them in the 1830s, though that would be hard to prove.

Paganini had such an influence, not just on other violinists, but on early Romantic composers such as Chopin, Liszt, Schumann and Berlioz, that he must have possessed more than just technical wizardry. Yet the problem is that the difficulty of his Caprices gets in the way of making music with them – if a violinist can play most of the notes in tune, that seems like an achievement in itself.

Vladislav Steinberg is a 31-year-old Russian who graduated from the Moscow Conservatoire and later studied with Yfrah Neaman in London. He came to the attention of a retired nurse, Catherine Long, who took an interest in him and put on this concert. Good for her – and after all, that's the way musicians have been promoted in the past.

Yet it's not easy, and it's probably unfair, to assess Steinberg's gifts from the considerable feat of stamina he accomplished. He played from memory – such pyrotechnics pretty well make that a necessity – and with remarkable sang-froid. He was graceful to look at, and his casual aplomb showed that he is a natural violin animal.

What I wasn't so sure about was the way he ironed out the contrasts in the music, and seemed concerned with smooth continuity at the expense of character. St John's is often described as a resonant building, but it tends to disperse the sound in its lofty space, so that players have to work hard for impact. In the octaves opening the third Caprice, Steinberg needed to be stronger and firmer; he played as if venturing on thin ice.

In the next one, Paganini's dynamic contrasts were hardly evident at all, though what violinist could get all those rapid double notes in tune? The two-part counterpoint of the eighth Caprice, with held notes against a moving line, was a slightly painful experience, but perhaps Paganini's contemporaries were so amazed at such a thing being attempted at all that they were oblivious to a bit of queasy intonation. Who knows?

And maybe my expectations were modified, or perhaps Steinberg really did improve as the evening went on. His octaves and double thirds got better. His rushing across the strings in No 16 made you realise how good he would be in music with more normal technical parameters; and the playful sallies of No 17 seemed unostentatiously natural. The almost offhand way he slipped into the tune of the famous variation-finale was engaging, and if he barely scraped the peaks of the closing roulades, who could blame him? Nice try.