For the October data, measurement was made with an in camera meter and a grey card, by December I had invested in a hand held meter and was able to make incident light readings. In each case I set the meters for ISO 100 and 1/125s
My observations are:
- The light changes very quickly at the start and end of the day (I just completed the twilight and sunset project photography (46/47) and discovered how quickly one must work to capture the changes in light.
- The winter sun was less than half as bright as the Autumn Sun
- The indoor ambient light (also from December) at f/0.8 is many times lower than the daylight outside, although this must be impacted by the window size and external reflections from buildings
- If I repeat this in summer or further south close to the equator the aperture will narrow even further for an ideal exposure. I have a trip to Indonesia in 2 months and will test that then.