This photo was shot in 1945 without a light meter - I know, because this is shot of your author age 1 in Fort Sam Houston Texas.
The focus wasn’t too good, but the exposure wasn’t off by much. How did my father do that??
Rather than a light meter, he almost certainly used the rule known as the “Sunny 16” which lets you estimate the exposure between 10 am and 5 pm accurately, without a light meter. You might ask why this is worth wasting your time on today when you already own a excellent meter in your camera.
The answer is that, even today, meters can give the wrong exposures, and it is always good to be able to estimate the correct exposure in your head without any tools but the understanding of the Sunny 16 rule.
Light meters get fooled when asked to meter very bright objects such as a snow covered landscapes, or a shot of the moon, or a very dark object like a black Labrador retriever. The reason meters get confused is that they assume everything in the area metered is a neutral mid range tone and then read its reflectance - the so called 16% gray card, but in the real world things are not always medium tones.
The Sunny 16 rule is based on INCIDENCE lighting, and will frequently be more accurate than most reflected meter readings that depend on the reflectance of the subjects. Incident metering does not depend on the subject, only the intensity of the lighting.
The Sunny 16 rule is based on the fact that the sun is equally bright everywhere outdoors between 10 am and 5 pm. So, if you know what the exposure is for sunlight at mid-day, then you can estimate it for cloudy or overcast situations.
The rule states that the proper exposure is determined by the ISO of the film/sensor setting. We will assume ISO 100. For ISO 100, at mid day with sunlit mid-toned object, set the aperture at f16, and the shutter speed at 1/ISO or 1/100th ( if your camera does not have a shutter speed of 1/100th, a setting of 1/125 if good enough for government work.)
sunnysunny 16exposuretutorialshooting tipssunlightphotographydaylightiso