The Sunny 16 rule has been around for a long time. In the early days of photography light meters were separate, hand held units. Photographers looked at the light and often gauged the exposure with their gut instance and experience.
No matter what kind of camera you use the most important thing is to shoot subjects that your feel passionate about. Photography is all about seeing with your mind's eye and knowing what you want the final image to look like before you press the shutter release.
The great thing about the Sunny 16 rule is that it works. To many it will seem odd to use a 'Rule' when we have state of the art light meters built into our cameras.
So why use the rule?
Some light situations are very difficult for an electronic light meter to 'figure out'. In high contrast scenes the meter can easily be fooled and you will end up with images that are either too dark or too light. The other thing the camera cannot do is read your mind - and to me it's all about what YOU see she you look at a scene. Remember you know what you want the final image to look like - your camera does not.
Taking responsibility for the end result. I shoot in RAW instead of jpeg. It takes the decision making away from the camera and puts it in my hands. By learning to judge light you take responsibility for how the image will turn out. It also just feels great when you get the results you want.
Guessing exposure and using the Sunny 16 rule forces you to look at the scene and judge it for yourself. What parts are standing out? Is the light flat or contrasty? What do you want the image to look like when done? I think you will be surprised how quickly you change how you look at light.
Here's the Rule:
On a sunny day set aperture to f/16 and shutter speed to the reciprocal of the ISO for a subject in direct sunlight.
If you are shooting at Iso 200 then your shutter speed will be 1/200s
If you are shooting at Iso 400 then your shutter speed will be 1/400s.
If you are shooting at Iso 800 then your shutter speed will be 1/800s.
Naturally you are free to use any equivalent exposure
I hope this helps. I'll be getting further into it in a future post.