On Dec 15, 1:20 pm, "Philip Eden" philipATweatherHYPHENukDOTcom
wrote:
"Philip Eden" philipATweatherHYPHENukDOTcom wrote :

0920z SW F4 28km 2Cu014 7Sc030 8As120 10.3/07.0 1020.0
RMK: This is getting boring1320z SW F5 35km 1Cu014 7Sc035 8As100 10.4/07.3 1018.2
RMK: Light levels seem to be lower now than they were 3h ago.





Philip Eden
Whipsnade 214m- Hide quoted text -- Show quoted text -

Yes, very gloomy here too. I pointed my camera out of the
window and read the exposure - about 1/15th at f/4.7, 400 ASA. This is
just about 1% of the level expected on a sunny day. The light level
is:

Square of f/number divided by exposure divided by ASA
rating

This gives a figure of around 40 for a sunny day. Today's
figure is 0.4. I have known values lower than 0.05 during "daytime
darkness" in thunderstorms. The eye is a very insensitive light meter,
a drop of 50% in light level not being really obvious.

Tudor Hughes, Warlingham, Surrey.