has only ever been captured once before?

[raymondaliasapollyon]

What do you mean? We have an example of this right here! You want me to find another example?

Yes, I'd like to find out if the example here is an exception rather than the rule.

 

[jutfrank]

Well, I don't know how you'd find that out other than by trawling through thousands of news reports or by asking people like the members of this forum what they make of such usage. In my judgement, there's nothing unusual or special about anything here—it's a perfectly normal use of aspect: a past event is talked about with present relevance: This is the second time that footage of whales has been been captured. Such footage has been captured only once before now.

 

[Tdol]

Once before now = news
Twice = old hat