[SECProto]

I would say you described "one seven millionth" of a second (1/7,000,000 s)

"Seven millionths" would be 7/1,000,000 s (7μs). They take 20 to 40 images in that period using 7 cameras, so any given camera might be as low as 1.4μs per frame.

[alberth]

Saying ~140k photos per second would have been a more understanding stat if only the article framed it that way.

[thfuran]

Yes, but they said seven-millionths of a second, not seven millionths of a second. Technically they're right that that's what it means, but I'd expect an editor to recommend against that phrasing in favor of the one you used to avoid confusion.

[thaumasiotes]

Well, it's true that the article says "seven-millionths".

I would guess it's a lot more likely that this is an editing failure, introducing a hyphen where no hyphen should be, than that they meant to divide a second into seven million equal parts.

For one thing, as SECProto alludes to, English would normally require you to say "less than a seven-millionth of a second" if that was what you meant. There's no such thing as saying "less than weeks". You have to specify less than how many weeks.

    less than (seven) (millionths of a second)

ordinary grammar, ordinary unit choice

    less than (seven millionths of a second)

improper grammar, bizarre unit choice.

[thfuran]

I agree based on the whole sentence in the article that that was probably an editing error.