5. how is shutter speed generally measured? what do the measurements mean?

Shutter speed is generally measured by the scientific symbol “s”. The measurement means that the measurements in "s" is the reciprocal of the number when the denominator is put on the numerator side instead. ... Aperture is measured by f's.

Shutter speeds are typically measured in fractions of a second, when they are under a second. For example 1/4 means a quarter of a second.r. The longest shutter speed on most DSLRs is typically 30 seconds (without using external remote triggers). hope this helped