Pixel sizeThe pixel size determines how many photonsone pixel of a camera chip can capture at a givenlight intensity. A square pixel with twice the laterallength can capture the same number of photonsin one quarter of the exposure time. This iswhy the size of the pixels is extremely importantwhen working with rapidly fading specimens,like in fluorescence microscopy.Quantum efficiencyThe exposure time at a given specimen brightnessis also dependent on how many electronsare released from the sensor per photon. Thenumber of released electrons determines howbright the structures appear in the image. Theratio between the number of released electronsand the number of captured photons is referredto as quantum efficiency. The higher this is, themore electrons are released per captured photon.The ideal value to be achieved is 1.