Indeed that is true. Some of my lenses are much faster than others! A fast lens does let me use a fast shutter speed, and as Wikipedia describes, that's where the phrases "fast lens", "slow lens", and "lens speed" came from.
But "fast f/1.4 shutter speed" doesn't just not make perfect sense, it doesn't make any sense. That's why I chose it as an analogy. The phrase doesn't mention lenses at all, it's talking about the shutter. And shutter speeds are measured in seconds or fractions of a second, not f-stops.
But "fast f/1.4 shutter speed" doesn't just not make perfect sense, it doesn't make any sense. That's why I chose it as an analogy. The phrase doesn't mention lenses at all, it's talking about the shutter. And shutter speeds are measured in seconds or fractions of a second, not f-stops.