The phrase "distinctive when" is correct and usable in written English.
It is typically used to indicate something specific or unique about a particular situation, and is often accompanied by an adjective or adverb. For example, "The restaurant was particularly distinctive when it dimmed the lights in the evenings."
Kinnear ignites terrifically into rage and despair but he is most distinctive when most contained.
There are many outstanding pieces of Japanese calligraphy in kanji, but they are not distinctive when compared with their Chinese counterparts.
And it encapsulates the sensation that Paris Photo is at its most daring and distinctive when photographic realities are literally or metaphorically tipped upside down.
But the candidate seems most distinctive when talking about making Americans feel "less lonely, less fearful and less isolated" in a changing world.
The film is least distinctive when in space-adventure mode – the slapstick gets messily frantic – but there are still touches of astonishing beauty, displaying the sheer grace that digital style can aspire to.
The seatbelt-clasp fastenings which made Kane's handbags so distinctive when he launched them last year reappeared as belts, sometimes looped inside peekaboo dresses and cinched tight against the skin.
But they give off strong gases — giving pools their distinctive smell — when the water is disturbed or when the chlorine destroys organic matter from swimmers.
What has made British film distinctive - when it has worked well - is the parity given to the writer as a creative partner rather than just someone who supplies a script.
And he heard some distinctive jeering when a close baseline call went against him.
Cameron at his worst, and incidentally most distinctive, is when he loses his cool.
There was even a very distinctive silhouette when fitted peplum tops were paired with sporty biker shorts.
