Guessing Exposures With Manual Cameras
The Sunny Sixteen Method
My Leica 111c left the Wetzlar factory in 1947, at the time very few (if any) cameras had built in light-meters, so my main problem was how to meter.
At the time I hadn't enough cash to buy a hand-held meter, so my options were to drag around my Nikkormat to meter with or just use my experience to make an educated guess.
I decided on the latter; but how educated could my guess be?
The system I decided on was the 'Sunny Sixteen' and it works very well, particuarly with negative film.
The Method is as follows:
First you choose the nearest shutter speed to match your film speed say 1/125 if you are using 100 ISO.
Then your aperture value will be set according to the light/weather conditions:
Sunny F16 (hard shadows)
Sun/Cloud F11 (soft shadows)
Cloudy F8 (barely visible shadows)
Overcast/Dull F5.6 (no shadows)
In bygone days the film manufacturers used to print his info with nice graphical representation inside the box, and this could be taped to the back of your camera.