Project 55 - light intensity

For this project I was asked to do the same as in project 38 but this time I have to measure the aperture vs distance from a light source. As I'm coming from an engineering background, before the project I already assume what the graph will look like - an exponential drop as we grow with the distance. And I was right:



In the book I was asked how many f stops would you have to open up the aperture to give the same exposure?Opening the aperture by one f-stop will let in twice as much light. Since the light level is 4 times less, we’d need to open up by two f-stops.

more was asked why this is not apply for sunlight - well, the distance of the sun from any object on earth is so big that it becomes irrelevant. BUT it will be interesting to make a photo in a normal camera of the moon and then to do that again on the moon itself and then to see the differences!