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. :cool:

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.

[Tin Can]

I cannot believe your 3 meters were that close! Not my experience at all.

I prefer using the box instructions on 35mm Kodak as I have done for 56 years, I am only 63.

And isn't it another 'rule' to slightly overexpose film and underexpose digital?

Now if I could just get my studio lighting down... burning more FP 3000 today!

[jbenedict]

Back when roll film always came in boxes, there was usually a chart printed on the inside, I've found that the chart works pretty well. The 'sunny-16" may fall apart when we forget that the details we want are lower in value and will need more exposure. The old, "Expose for shadows, develop for highlights" rule. Consumer film can adapt itself to many things and especially overexposure. But, in the case of shadows, it cannot render something that hasn't been put there so it is important to get some light into those shadows.

[Mark Sawyer]

Sunny sixteen is a lucky accident of alliteration. (See? It happens more than you think!) The funny thing is, it stayed the same in 1960, when they recalculated the film speeds so all the ASA's doubled, (Tri-X and HP3, for example, went from 200 to 400), although the emulsions were the same.

Here in Arizona, we usually follow the Sunny go inside and have a beer rule...

[cyrus]

If I'm not mistaken, the Sunny 16 rule also requires you to round-down shutter speed --since there is no 1/100th stop, but there is /125th --down to 1/60th. But in any case the Sunny 16 rule was applied to BW film which has a wide lattitude of exposure.

[Tin Can]

I always had good fortune with Sunny 16 shooting square 35mm Kodachrome, aka 126 format.

This 1964 World's Fair Mustang conv illustrates that. I was 11 and had no idea what a meter was.

Obviously this an an example only and NOT LF. View with caution.

118430

[BrianShaw]

...Obviously this an an example only and NOT LF. View with caution.



I hope the "LF police" will forgive that transgression. Nice pic. Reminds me of the car that my 3rd grade teacher bought that same year. Oh... I was sooooo in love with both her and her car. She jilted me later in the school year by marrying someone her own age. Miss McGowan, if you are reading this... I never forgave you but if you want to come groveling back you'd better still have the car!

[Corran]

Down here in the summer it's more like Sunny 22...

Sunny 11 in the winter/evening though!

[Keith Fleming]

In the many years I lived in Northern Virginia, I found the Sunny-16 rule to be accurate, and that, plus the charts and diagrams in the film boxes, allowed me to get good at guessing the correct f-stop for the conditions. Then I moved to the Olympic Peninsula and found my "expertise" no longer worked. I went back to using a meter almost all the time, but I would say the Sunny-11 rule is a much better model to follow here.

Keith

[BradS]

I think latitude makes a difference.


Yes. Very definitely latitude makes a difference. As does time of year and time of day.

[jcoldslabs]

So what you're all saying is, the "Sunny 16" rule works just fine....except when it doesn't. :p

Call me technology-dependent, but I'm sticking with my light meters!

Jonathan

[Tin Can]

Yes, because you often shoot inside. I used to never shoot inside, because it never worked for me, as a kid.

I am still having troubles inside...


So what you're all saying is, the "Sunny 16" rule works just fine....except when it doesn't. :p

Call me technology-dependent, but I'm sticking with my light meters!

Jonathan

[DannL]

Most of us humans are born with two light meters in the front of our skulls. Now, whether they work "properly" is a different issue. But, most of us can distinguish between colors at many different levels. So, training the brain to recognize certain levels of light (or brightness) should be a simple task . . . one would think.

[Greg Miller]

The sunny 16 rules applies at mid-day in full sun. Who the heck is shooting at mid-day in full sun????

[jbenedict]

I always had good fortune with Sunny 16 shooting square 35mm Kodachrome, aka 126 format.

This 1964 World's Fair Mustang conv illustrates that. I was 11 and had no idea what a meter was.

Obviously this an an example only and NOT LF. View with caution.

118430

That Kodachrome sure was nice stuff. Will anyone still have a cellphone selfie in 50 years?

[Stephen Benskin]

Sunny 16 is connected to the variables in the exposure equation. This is an excerpt from the APUG thread "Is the K factor relevant to me or should I factor it out." The title is about middle gray which includes Sunny 16.

118443118446118448

[Teodor Oprean]

This is a total guess on my part, but I think the Sunny 16 rule is so called because f/16 is the minimum aperture needed for sufficiently usable depth of field with a 4x5 press camera equipped with a stock lens (focal length 127 mm or 135 mm). This rule of thumb for guessing the exposure in bright sunlight coincides with the rule that you should stop down to at least f/16 when using an Optar / Ektar / Xenar / Tessar with 4x5.

[jnantz]

jonathan

http://www.blackcatphotoproducts.com/guide.html
it works pretty well .. if you have the time and energy to use it ...
i've had mine for almost 20 years ago when i got it from mr black cat himself
nice guy !
john

[Peter Gomena]

I found sunny 16 exposures always left me with empty shadows. Sunny 11 works much better. I usually have a light meter handy and use "guess exposures" only in emergencies or when I'm packing a junk store camera for one of those photo outings where spontaneity and silliness is more important than a bag full of gear. How it all evolved is beyond me, but if you look at the typical exposure instructions given with amateur cameras in the "old days," you'll see they tell you to photograph with the sun over your shoulder fully illuminating your subject. Ugly light, perhaps, but it helped guarantee consistent exposures. If your roll of Verichrome Pan was exposed within a stop, you were safe.

[Tin Can]

Mr Black Cat has his 26 shades of grey. Interesting and patented.


jonathan

http://www.blackcatphotoproducts.com/guide.html
it works pretty well .. if you have the time and energy to use it ...
i've had mine for almost 20 years ago when i got it from mr black cat himself
nice guy !
john

[jcoldslabs]

jonathan

http://www.blackcatphotoproducts.com/guide.html
it works pretty well .. if you have the time and energy to use it ...
i've had mine for almost 20 years ago when i got it from mr black cat himself
nice guy !
john

I think what matters is to choose one method of determining exposure and sticking with it, whether it is this Black Cat guide, the Sunny 16 rule or a modern light meter. Any method will work provided you learn its limitations and nuances over time. (As has been discussed above, Sunny 16 is time of day and latitude dependent.) These days I use my spot meter for everything, even when I'm not going "full Zone System." When I want a quick average reading I use a small gray card.

I haven't tracked it, but I would guess that 80% of my exposures (which are often made indoors by window light) are shot between EV 7 and EV 11. If I could simply memorize which lighting conditions correspond to which EV I would be set.

Jonathan

[Heroique]

Any method will work provided you learn its limitations and nuances over time. (As has been discussed above, Sunny 16 is time of day and latitude dependent.)

Yes, field experience will evenually lead to one's own reliable "sunny" rule.

I'll only add this for one who doesn't already have a personal "sunny" rule: No matter the time of day or latitude, it's easy to miss (i.e., not account for) the thin, hard-to-notice, 1-stop-robbing layer of haze or pollution on most "clear" days.

Perhaps this is one reason why sunny-11 is getting more love around here than sunny-16. ;^)



The sunny 16 rules applies at mid-day in full sun. Who the heck is shooting at mid-day in full sun????

This was worth the chuckle it was meant to provoke! But I hope it doesn't mislead the many beginners around here. In other words, the sunny-16 rule is where to start figuring exposure, not where to end it. The over-simplified thinking might go something like this: "If it were a perfectly sunny day at noon at the correct latitude, my "sunny-16" exposure would be [X]. But since my lighting conditions are not perfectly sunny, and it's not noon, and I'm not at the correct latitude, I will adjust my exposure [Y] stops from [X], choosing a combination of shutter speed and aperture appropriate to my composition." Of course, with more field practice, one would use a "personal sunny rule" – not necessarily the sunny-16 rule – to determine the starting point [X].

[djdister]

Sunny 16 certainly worked for me in Colorado, a bit less so in Maryland (must be the pollution).

[Lenny Eiger]

I always thought the rule was for Tri-X, which at 200-400, would handle this fine. I understand there may be a shot where something is happening very quick and there's no time to use a light meter. Barring that, stop being so damn lazy. Geez, having to consult a light meter? They aren't the heaviest thing in the backpack and one can use the zone system and actually get more than you can get with an incident meters' basic reading. It's part of what is great about large format...

Lenny

[BradS]

..... the sunny-16 rule is where to start figuring exposure, not where to end it. The over-simplified thinking might go something like this: "If it were a perfectly sunny day at noon at the correct latitude, my "sunny-16" exposure would be [X]. But since my lighting conditions are not perfectly sunny, and it's not noon, and I'm not at the correct latitude, I will adjust my exposure [Y] stops from [X], choosing a combination of shutter speed and aperture appropriate to my composition." Of course, with more field practice, one would use a "personal sunny rule" – not necessarily the sunny-16 rule – to determine the starting point [X].

YES! many people seem to miss the fact that sunny-16 (or, sunny-11) is where one starts to estimate exposure....it is the starting point and rarely, then end.

[Joe Smigiel]

Stephen's post expands upon my presumed and simple understanding of the origin of the Sunny-16 Rule. In one of his books, Ansel Adams referred to the "Exposure Formula" as relating the "key stop" for the required aperture at the reciprocal of the luminance in candles/square foot of the subject for the shutter speed. IIRC, he mentioned the luminance of the midlatitude clear north sky as 256 footcandles in an example. The key stop was defined as the square root of the ASA (ISO) of the film in use.


So, if we take something like Kodachrome 64 as the film, the proper exposure for the sky would be:

f/√ 64 @ 1/256 seconds

= f/8 @ 1/256s
= f/11 @ 1/128s
= f/16 @ 1/64s which is the Sunny-16 Rule value (f/16 @ 1/ISO seconds).


Sunny 16 is connected to the variables in the exposure equation. This is an excerpt from the APUG thread "Is the K factor relevant to me or should I factor it out." The title is about middle gray which includes Sunny 16.

118443118446118448

[Kevin Crisp]

My first decent camera was a Spotmatic and I was working for a school paper. I loved Plus-X back then (not sure why...guess I like purple) and I always used 1/1000th when possible because I thought that was very cool after suffering with an Exa Jr. and its top speed of 1/150th or something like that. It didn't take long to realize that in So. Cal. f:5.6 and 1/1000th with the sun to my back seemed to nail it. Most of the time I never bothered with the meter after that. Today, on a sunny day, it will get you in the ballpark.

Now that I use LF and am regularly committing what a 35mm photographer would consider gross overexposure, I don't use it except as a rare teaching idea.

What I have noticed when using Tri-X in sheet film size, is that if I look through my exposure records about 80% of the exposures are the same. And that isn't in the sun.

[WayneStevenson]

I paraphrased this bit I wrote in another sunny 16 discussion from a few years ago.

Sunny 16 isn't an exact exposure. It is an assumed exposure that should encompass a scene's highlights, mid-tones, and shadows at what would normally be aesthetically pleasing to a reasonable person, with a reasonable dynamic range.

With the intent of putting your neutral gray, at neutral? For all intents and purposes you're likely to get a usable exposure provided that your subject is not far in the highlight or shadow range of tones. For your own liking.

Using good judgement / experience however, will tell you if you're shooting a highlight, or shadow. And you can adjust your exposure to accommodate the variation from your mid-tone.

Sunny 16 is considered an incident reading? But it is not a scientific formula. It's an ESTIMATION and will not give you any exactness. Even your shutter speed selection is not going to be the reciprocal. It's going to the be the closest option to it. It goes without saying that that isn't exact..........

It's a little nursery rhyme to help you out to get USABLE exposures that will yield USABLE prints without the use of a light meter. Through choice, ability, or circumstance.

It doesn't even address the deviation from the equator. Here in Alberta, Canada, it's a Sunny 11 rule.

Sometimes Sunny 8 depending on the time of year.

[Stephen Benskin]

Here are a couple of pages from the ANSI Photographic Exposure Guide - ANSI PH2.7-1986. It gives the Incident Values for different Latitudes for different times of days and throughout the year. The rest of the book has exposure adjustments for various weather and lighting conditions. The information is derived from Loyd Jones' paper, "Sunligh and Skylight as Determinants of Photographic Exposure."

118639 118640


This example is a little "proof" I put together on Sunny 16 and the exposure equation.

118641

[Emmanuel BIGLER]

Thanks to Stephen Benskin for sharing all this information!

I don't know if the sunny-16 rule works for you, but for me it is a useful thing to remind "when everything else fails", since I'm living close to 45° of latitude.

And actually the sunny-16 rule DID work very well 45 years ago for some very special photographers (MF, not LF, sorry) who were orbiting around the Moon in the Apollo-8 vessel.

Look at, and listen here to this invaluable combination of true sound, real videos (??), and computer-reconstructed graphics. (http://bcove.me/lgslnb8b)
at about 2:30 in the video,
Lovell: "Well, I got it right, aw, that's a beautiful shot ! Two-fifty-f-eleven"

(ahem ... may be it was not 125 ASA film, though ;) )

This is not NASA's exposure meter, but it is very useful
http://expomat.tripod.com/
(the name of the author seems to be Dave Harris, NZ)
http://expomat.tripod.com/pdf/ExposureMat.pdf (http://expomat.tripod.com/pdf/ExposureMat.pdf)

[Jim Andrada]

I usually think of Sunny 22 here in the desert. But as my fellow Tucson-an (where the "cold" water this time of year is almost warm enough for C-41) Mark Sawyer said, who in their right mind wouldn't rather be inside with something cold at noon on a balmy 110 degree summer day.

[Tin Can]

I was just going to ask in a new post, hows the water temp around the world now.

Chicago cold tap is about 62 degrees F right now and my water heater barely runs.

[Corran]

Lucky you. It's 80F out of the tap here in the deep south, as it is for over half of the year.

[Tin Can]

Yes, but I bet it you seldom have 90% ice on your lakes. We were using ice breakers on our water supply (Lake Michigan) most of the winter and Lake Superior had ice until the end of June.

I prefer cold over hot, we hit 90 today and I never left the cave.


Lucky you. It's 80F out of the tap here in the deep south, as it is for over half of the year.

[jcoldslabs]

Lately I've been having to add ice cubes to the tap water to bring it down to 68°F when mixing one-shot film developer (HC-110 & Rodinal). I think straight out of the tap it runs around 72°F right now. Despite a few hot days our summer here in Portland has been a mild one so far.

Jonathan

[jcoldslabs]

I came across this in a box of old photo stuff. With instructions this complicated, who WOULDN'T want to use the Sunny 16 rule?


http://www.kolstad.us/ebay/MISC_The-Photo-Beacon-Exposure-Card_1906.jpg

Jonathan

[Jim Jones]

Two years after Todd published his Photo-Beacon Exposure Card, my mother was certified to teach 3rd grade. Judging from the textbooks from that time, her students, unencumbered by calculators and light meters, would have had little trouble in using Todd's card.

[Mark Sawyer]

Today's third-graders would pull out their iPhones and check their Sunny Sixteen app...

[Tin Can]

The Photo-Beacon card is very easy with only single digit addition. Maybe today's wiz kids could do it without a phone...

The best thing I ever learned in math, was to do it twice. Once with very round numbers to get in the ballpark and determine decimal place. Then use a slide rule for better resolution.


Two years after Todd published his Photo-Beacon Exposure Card, my mother was certified to teach 3rd grade. Judging from the textbooks from that time, her students, unencumbered by calculators and light meters, would have had little trouble in using Todd's card.

[BrianShaw]

118923

... from about the same era as the Photo-Beacon.

[Harold_4074]

The "sunny sixteen" rule definitely goes back to the 1930s or before; my father used a Kodak book as a text in his Georgia Tech photography course back then, and it covered both the basic rule and the exceptions (light clouds, open one stop; heavy clouds, open two stops, etc.)

He was fond of repeating the instructions that he gave to his Signal Corps photographers: f/8 at 1/250 second, and always use a flashbulb, indoors or out, day or night. And don't mess with the focal plane shutter!

The film was probably something like Super Double-X, and there might have been some pretty heavy negatives, but I know that it is possible to get a print out of a negative that is almost opaque, if you have grade 4 paper on hand and use warm, concentrated Dektol. (Please don't ask me how I know this....:) )