Sforzando in forte and sforzando in piano

[dlipatti]

So, lately I've been listening to some of Andras Schiff's lectures on the Beethoven sonatas. In one of them - I think it's on the very first, actually - he points out that there is a big difference between a sforzando written out in a piano-section, and one written out in a forte-section, without specifying any further. Could anyone please tell me what he means?

[stevebob]

I couldn't say with absolute certainty what someone else meant, but my understanding is that an sf (or sfz or fz) doesn't represent an absolute value of loudness but rather is relative to its context.  In a pianissimo passage, it would stand out when played mezzo-forte; in a passage played forte, the sf would need to be fortissimo.