If the concrete is poured while the ground is wet, it will not form a solid foundation  If the concrete does not form a solid foundation, it will either settle unevenly or crack
So if the concrete settles evenly, either it was poured while the ground was dry or it will crack
The camera will work properly only if the film is properly exposed. But the film cannot be properly exposed if there is either not enough or too much light. So the camera will not work properly if there is either too much or not enough light.