Originally posted by MadMathMind When shooting at large f numbers in very bright light, even at the lowest ISO settings, it's pretty easy to reach shutter speeds of 1/2000 or higher.
High shutter speeds are really not much of an issue from a mechanical perspective. The actual velocity of the shutter curtains is much slower than you might think. What makes for the different speeds is the time between the start of the leading curtain travel and that of the trailing curtain.
In the old days (say 1/1000s max) the curtain velocity was the same for all exposure times with the leading curtain completing its travel in the amount of time indicated by the X flash sync speed. That would generally be 1/60s for horizontal run shutters or 1/125 for vertical run. On modern shutters the curtain velocity is stepped into two or more ranges to allow for consistent timing, but the idea remains the same.
The shutter on the vintage Zeiss Contax rangefinder cameras (and their clones, the Kiev), the vertical shutter is amazingly slow with the leading curtain taking about 1/35s to drop, yet the minimum exposure time is nominally 1/1000s. It is a marvel to watch.
As for the sensor...It reacts to the light that strikes it. That is the essence of exposure control. The same number of photons strike the sensor for f/8 @ 1/125s as for f/5.6 @ 1/250s and also f/1.4 @ 1/4000s for that matter.
Steve