Origins of the Sunny 16 Rule?

[jcoldslabs]

Yesterday was a bright sunny day here in Portland and, being curious, I decided to check my meters against the "Sunny 16" rule. I used three different meters and three different methods: incident, reflected and spot. I went out into the yard at midday and took an incident reading in bright sun with the white dome held aloft and pointed back at the house. I also took a 1° spot meter reading from a grey card in the sun, and lastly I went back up on the porch and metered the yard where I had been standing with a Gossen Luna Pro F in reflected mode.

The result? All three meter readings were within 1/3 of a stop of each other (thank goodness), the average reading being EV 14. At ISO 100 this works out to 1/60 at f/16. The Sunny 16 rule for this ISO would indicate 1/100 at f/16, almost a full stop less. I realize Sunny 16 is a crude approximation, but many people swear by it.

So the question is, where did this rule come from? If my metering experiment is any indication, it should be "Sunny 11."

Jonathan

[Michael_4514]

Seems to me that being within one stop is pretty good for a rule of thumb. Most film can tolerate this range of underexposure. People swear by it because it works. I don't know that anyone uses the sunny 16 rule when they have a meter on hand. For me, it's always been something to use when I find myself without one.

[jcoldslabs]

It also makes sense that, like most aspects of the photographic process (exposure index, development times, etc.), this "rule" should be interpreted on an individual basis. Going forward if I find myself without a meter on a sunny day I'll use the "11" variant mainly because, in general, I prefer to err on the side of slight overexposure rather than under.

J.

[Michael_4514]

Now that you mention it, I realize that whenever I've used the "rule," I've always fudged toward overexposure as well. In other words, even though the rule is sunny 16, in actual practice, I've probably applied it as closer to your sunny 11 results.

Given the ambiguity inherent in such a rule, I would imagine that to be the general tendency. Makes me think that if we had a "sunny 11" rule, the ambiguities would still be there and we would be inclined to resolve ambiguities in favor of even more overexposure, perhaps leading to too much exposure?

[jnantz]

hi jonathan

i am not sure who invented it ... but from what i remember it is only f16 in northern climes, so
your f11 approximation is dead on. i hate using a meter so i tend to sunny11 .. ( can't complain )
the kodak sunny 16 pictograph is printed now in every box of kodak film and before that on a slip of paper
and before that similar exposure "instructions" came with cameras like the graflex national II rollfilm cameras
(folmer graflex had it printed on the case so when you flipped it up to adjust the shutter you could notice conditions and compare to the chart )
i am guessing other camera companies had similar information printed on the bodies of their cameras that eventually
became known as sunny 16 ...
or .. maybe i am wrong

john

[Bill_1856]

Probably in the early-mid 1970s.
I grew up (photographically) in the '50s. My standards of learning were: Popular Photography, Modern Photography, US Camera, The Leica manual, and Graphic Graflex Photography. The "Sunny Sixteen" rule was never mentioned in any of them, but long, complicated algorithms for various conditions of weather, time of year, and location.
Every roll of film came with it's own cheat-sheet of exposure suggestions. ASA (ISO) speeds didn't vary all that much, from about 10 for Kodachrome to 100 for Super XX.
It wasn't until Patricia Caulfield's book on the Everglades was published in 1970, with all it's beautifully exposed images, that someone recognized that the whole project was made using cheat-sheet exposures (no meter), and someone noticed that the "sunny 16" rule -- worked better than most meters of that day.

[David Schaller]

I have found, as you did, I prefer sunny 11. I primarily use it when I'm in a situation, with snow or water, that has a lot of reflected light bouncing around that would lead to under exposure from my metering. Other people would adjust the meter, or just meter and add a stop.

[BrianShaw]

You only get EV14 at noon. We get EV15 - EV17 at noon. I think latitude makes a difference.

somewhere I have a table from an old photo book that helps adapt exposure times for contact printing based on latitude. The differences are noticable, as are the differences based on time of year... and believe it or not the differences based on time of day are noticable too.

[Jim Jones]

The Sunny 16 rule was practiced soon after the introduction of the Weston light meters and the Weston film speeds associated with them in 1932, although the name Sunny 16 may not have been used then. If a Sunny 11 rule seems more accurate today, remember that film speed numbers were adjusted upwards in 1960 to eliminate an exposure safety factor (and perhaps to make the buyer believe that the films were actually faster).

[DannL]

I think for the Sunny 16 rule to work properly, you need more light. Are you tired, run-down, listless. Do you poop-out at parties? Are you unpopular? You probably need more light.

As previously mentioned, your latitude should contribute some to your reading of only 14. Weather, haze, pollution, humidity, time of year, will all contribute to some degree. At my location 35° 28' 3" N, which is 10 degrees further south than Portland, I took an incident reading of the sun yesterday which calculated EV15. The sun was partially covered by a very thin high-altitude cloud layer. Then I took a reflected reading of the palm of my hand, subtracted one, and got another EV15.

In the old days prior to meters, popular photography publications published monthly tables and equations for calculating a good exposure for plates and films. They can be quite tedious. Some of these publications can be found on Google Books online.