1) Eyes don't work like cameras; there's no real "exposure" phase as such (even though there's lots of thresholds). So it's misleading to talk about discrete images that we sample at some fixed frequency. Instead, it's much more helpful to think of photoreceptors and subsequent processing stages as continuous band-pass filters. At some point, high frequencies are simply cut off because the electro-chemistry of the cell can't keep up. For us, that cut-off comes earlier than it does for invertebrates.
2) There's no mechanical interaction between light and photoreceptor. Instead, the transduction cascade of the dipteran eye seems to encompass a mechanical (as opposed to biochemical) step.
3) It's pure conjecture to talk about a fly's slowed down "perception" of the world. The reason why they take off before you get to them is much simpler -- there's a highly optimized reflex that connects eye and flight muscles via the giant fiber (a particularly rapid nerve). We have similar responses, like eye lid closing etc. Additionally, their photoreceptors are sensitive and fast. But there's zero evidence that flies have any sense of continuous time that could be faster than ours.
Ah, well. The perils of science journalism.