The sampling frequency is the number of cycles of the measured clock in one second with a unit Herz(Hz).
fs=1/T=1/(one period of the measured clock)
In the imaging sensor chip, frame rate is the rate at which an imaging device displays an consecutive images called frames. It is to measure the number of frames in one second the imaging chip could offer in a unit of fps.
As we known, the ADC has been used in the output interface to generate the bit to convert the analog signal captured by the each pixel. So the sampling frequency of the ADC has a relation of frame rate.
fs=(number of pixels in imaging chip) x (frame rate).