How to find correct exposure without a light meter

In days of old when knights were bold and light meters weren’t invented.

Sunny 16 ruled supreme and overexposure was prevented!

The sunny 16 rule is a way of getting a correct exposure in daylight without a light meter. For those of you who can remember film, this used to be printed on the inside of the film boxes as a guide.

The basic rule of thumb is ISO = Shutter speed plus the following.
on a Sunny day with 100 ISO selected the exposure would be ƒ16 with a shutter speed of 100th second or 125th if your camera only gives you that.The sunny 16 rule come to pass when an exposure for the brightest common exposure was needed. Mid-day sun without cloud. So the basic rule is, “on a sunny day set the aperture to ƒ16 and the shutter speed to the reciprocal of the ISO speed” for example:

  • 200 ISO selected it would be ƒ16 with a shutter speed of 200th second or 250th

The variants of this are in the table below. Adjustment for varying climatic changes can be learnt pretty easily once you know the basics. You’ll be amazed at how accurate the guess can be. Learn this one and amaze your peers with your perception of light. Be the human light meter!

Aperture Lighting Conditions Shadow Detail
f/22 Snow/Sand Dark with sharp edges
f/16 Sunny Distinct
f/11 Slight Overcast Soft around edges
f/8 Overcast Barely visible
f/5.6 Heavy Overcast No shadows
f/4 Open Shade/Sunset No shadows