This exercise (p146) comes in 3 parts. The first is a comparison between sunny and cloudy weather for three types of scenes, the second is finding opportunities for best using the diffuse lighting that comes by overcast weather and the third is rain. This post covers part 1 only, part 2 & 3 to follow shortly.
So, for part one we are to take a street scene, a building and people, shoot them (with the WB set to sunny) when the sun is out and when the sun is behind clouds and see what the differences are.
Theres an obvious difference in exposure (1 stop) but also the building under cloudy weather is much less warm in tone despite being shot with the same WB. The contrast is higher and the shadows are deeper in the sunny photo.
Secondly a street scene,
This time there is a larger difference in exposure: 1-2/3 stops. The overcast photo looks very dull and flat compared with the sunny one. Again you see the sunny one is warmer in tone.
Lastly, people, they didn’t hang around so long in the sunny area so I have different sets of people walking through the same area.
This again was about 1-2/3 stops difference in exposure (by the way I was using this nifty little stop difference calculator here). This time we see that the cloudy one is nicer because the people are squinting less against the sun. There are less harsh eye-socket shadows in the cloudy photo too (although it was still quite bright). And although the buildings seem less warm the peoples skin seem ok in colour in both photos.