Lessons from the Shot: Rule of Thumb Exposures by George Hsia

 

By George Hsia, www.georgehsia.com
 
Figure 1
 
In life, like photography, there are a handful of rules that every photographer should keep in mind.  
 
Sunny 16 Rule – Rule for determining exposure (shutter speed, ISO and aperture) on a right and sunny day. When the sun is not covered by clouds and shadows are distinct, the Sunny 16 rule says that proper exposure can be achieved with f/16, 1/100 and ISO 100.
 
Slight Overcast – In slight overcast conditions, the sun is partly covered by clouds but is still strong and shadows are soft around the edges.  Lighting conditions should be about 1 stop less than Sunny 16, so proper exposure can be achieved with f/11 and appropriate ISO and shutter speed (i.e., ISO 100 and 1/100 sec or ISO 200 and 1/200 sec).
 
Heavy Overcast – In heavy overcast lighting conditions the sun is completely covered by clouds and shadows at not visible.  Heavy overcast conditions are one stop less light than overcast conditions and three stops less light than sunny conditions so proper exposure can be achieved with f/5.6 and appropriate ISO and shutter speed.
 
Open Shade – Open shade is the shadow cast by a large object in sunny conditions. Open shade has one stop less light than heavy overcast conditions and has four stops less light than sunny conditions so proper exposure can be achieved with f/4 and appropriate ISO and shutter speed.
 
If you don’t have a light meter handy, it’s better than a poke in the eye.