If it is at the focal plane all the rays from a particular direction will again converge to a point. Remove the focusing jig. Copy it to a floppy. Exposure Time Now explore the effect of exposure time. The CCD works by collecting electrons freed in the silicon of the chip by the incoming light.
More light means more free electrons where it hit.
So we expect the signal to be proportional to the length of time the sensor was exposed to light and the intensity of the light. Each pixel has the capacity to hold about 80,000 electrons. Take an exposure for the minimum time of 0.11 seconds. Select the histogram option and push reset. The range will be from 0 to 65535 counts, representing the 16 bit resolution of the analog to digital converter used in the camera.