It probably depends on how the button is debounced as well. Software and physical debounces are both generally tuned for at least a few milliseconds and potentially over ten milliseconds of latency.
A better trigger could be built by interfacing a microcontroller over USB HID and having it send a simulated keystroke or button press at the same time as turning on an LED.
I think you're being generous. I've had microswitches that needed a good 20-25 mSec to fully debounce. Good quality sealed switches (like Cherry) too, not badly plated counterfeit stuff.
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It probably depends on how the button is debounced as well. Software and physical debounces are both generally tuned for at least a few milliseconds and potentially over ten milliseconds of latency.
A better trigger could be built by interfacing a microcontroller over USB HID and having it send a simulated keystroke or button press at the same time as turning on an LED.
I think you're being generous. I've had microswitches that needed a good 20-25 mSec to fully debounce. Good quality sealed switches (like Cherry) too, not badly plated counterfeit stuff.