Proving Sunny 16

This is definitely the funniest thread I've read here in a while.

 

Are you seriously making a big deal about this?

 

Sunny-16 is just a guideline. It's not gospel. In fact, all exposure is really arbitrary isn't it? I could guesstimate an exposure with sunny-16 or I could use my spotmeter and find all the values in the scene and average them; neither exposure would be the "correct" one.

 

Your point is to get us to question our complacency? Even after I manage to get past the inherent arrogance of your assumption that all people who use Sunny-16 are complacent boobs, I still don't understand what in the living hell you're getting at.

 

Sunny-16 "works" for alot of people because they've found that shooting at an exposure EQUIVALENT to 1/ISO @ f/16 gives them the tonality and shadow detail, etc. they consider desirable given their their particular developer, latitude, religion, star sign, birthdate, inseam, age, mailing address, # of dependents, handedness, nationality and shoe size.

 

Some people might like exposures where a clear north sky shows up as a Zone 3 grey. Sunny-16 would not be for them. These people don't use Sunny-16, but I wouldn't call them enlightened either.

 

If you want to know what makes middle gray "middle gray", or how to calculate film speed, you need to study sensitometry. If you want to learn about sensitometry, ask questions about sensitometry; making posts in an attempt to "wake the masses from their Sunny-16 slumber" makes you look less than informed.

John, I would delete the thread if I could. It really didn't go right. I made a mistake, sorry. The idea isn't about the complacency of people who use Sunny 16, but how each of us need to reevaluate, do further study if you will, from time to time the things we think we know.

 

If there is a rule of thumb, then it is that if a post can be misunderstood, it will be misunderstood. I personally didn't have a question about Sunny 16. I was attempting to create a discussion about it. Look in the above mentioned thread on Over exposure. I do know sensitometry, sensitometry is a friend of mine, and the Sunny 16 thread was meant to discuss another aspect, exposure theory.

Few lenses have maximum apertures smaller than f16, and for many f16 is the optimum aperture. 1/iso is very convenient as a baseline from which to deviate. If one was interested in formulating a guideline for estimating exposure without the benefit of a light meter, the 1/iso shutter speed would be an attractive starting point, and the f16 aperture is in the middle of the aperture range of most cameras, allowing for deviation in either direction. It works because the latitude of the films is wider than the deviation in the illumination from a cloudless sky. Unless I'm missing something, which is not unlikely. If so, I hope you'll enlighten us all. I enjoy a good twist ending.

I enjoy asking philosophical questions and even have a degree in doing so, and there are many interesting and profound things that have to do with things like exposure, and some of them are not even technical, but perhaps psychological, aesthetic, historical, and maybe even philosophical. We might ask, for instance, why after Adams it became a norm to attempt to produce a full range of tones, while at the turn of the century, many images that contained a rather narrow range of tones were considered successful--just to consider one example.

 

I don't think interrogating the "sunny 16" rule, though, is going to take us to great depths. If you believe it can, then the way to go about it is not to raise an open question about the "sunny 16" rule, but to propose a specific objection, that will reveal some problem with the rule.

 

Part of being able to have a good philosophical discussion is being able to distinguish between what is interesting and what is trivial. We should ask questions about what is interesting, but complacency about the trivial is itself trivial.

<i>"I personally didn't have a question about Sunny 16. I was attempting to create a discussion about it."</i></p>

 

Don't we call these people trolls? Rule of thumb: DNFTT (Do not feed the trolls).

Mea culpa, mea culpa already for God's sake. The horse is dead. The parachute is a backpack.

Stephen and I tend to think about things in the same way, though he's far better at the analysis end of it. This quote from Lord Kelvin may explain how Stephen is encouraging us to look at the world:

 

�I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it, but when you cannot express it in numbers, your knowledge is of a meager and unsatisfactory kind; it may be the beginning of knowledge, but you have scarcely in your thoughts, advanced to the stage of science, whatever the matter may be.�

 

Photography is a science, and even after all the years of how-to books and formal texts, there are still quite a few issues with tonal reproduction that haven't been properly tied together. Stephen is actively working ont that. Admittedly, not everybody has an interest in that part of the art/hobby/craft, or whatever it is, but the knowledge can help you get to the "look" you might be after.

I enjoy both the scientific and artistic sides, scientific by training, artistic by passion for photography.

 

You've got sunny 16, and theres a whole bunch of other variations too... like sunny day but not really a clear sky its f11. shady f8 for open shade, cloudy days are 5.6 and so on. At least I think thats how they go, its been a while and I tend to remember them when my battery dies. Hasn't failed me yet.

 

These work simply because of repetition, if its repeatable we can generally assume it to be a fact. There are places this wont work, like scotland as mentioned above. But in a good many places around the world a clear sky on a sunny day is pretty much the same amount of light. Or at least close enough for it to not matter.

Why is there a State street in Rochester?<BR><BR>What is Kodak found out we as kids put vinegar and baking soda in those Kodachrome metal cans; and caused a ruckus with the school teachers?<BR><BR>Is there any proof of our behavior?<BR><BR>What if we got caught?:)<BR><BR>What if Sunny 11 works better?

Just because I'm the Scandinavian poster who uses "Sunny 11", I'll give my contribution to this already dead horse.

 

Like the explanation for why the sky is blue, the "sunny 16" rule is scientifically incorrect, but good enough for everyday use - unless you happen to know better.

Dear Stephen,

 

Oh, dear, some people do hate thinking, don't they? And they love insulting those who do think occasionally. Why are they so willing to assume you are an ignoramus, and then start lecturing you as if you were a dimwitted child? You know a lot more about this than I do, and I'd not call myself a complete ignoramus on the subject. I think it's an interesting question, and if in your opinion there's any more to it than what I've summarized below, I'd be interested to hear it.

 

From common experience, exposure on a sunny day is more or less constant to within about +/- 1 stop, depending on latitude and surroundings.

 

For a particular fixed and reliably determined film speed, call it X, this constant exposure must be close to 1/100 at f/16. It is also of course 1/50 at f/22 and 1/200 at f/11.

 

By a happy coincidence -- and I think it is nothing more, though you have thought about this a great deal more than I -- under the ISO system, X happens to equal 100, so we use a sunny 16 rule. If X happened to equal 50, we'd use a sunny 22 rule.

 

As for the accuracy of 'sunny 16' I'd say it's probably pretty good with uncoated lenses but that with the lower flare factors of modern lenses 'sunny 11' is a better bet for mono with decent shadow detail. With transparencies, where exposure is keyed to the highlights, the difference between coated and uncoated lenses is unimportant, and 'sunny 16' probably works better on average. But most people are incapable of understanding that optimum negative exposures and slide exposures are determined in different ways -- that they coincide only across a limited range of subject brightness ranges -- thus leading to a single rule that will do best with transparencies.

 

Given that ISO speed determination for negative films is based on the exposure (measured in lux-seconds for ISO standards) that gives a density of 0.10 above fb+f, and has no relation to sunshine, I don't see that it can be a lot more than coincidence.

 

There's also the point that the 0.10 density itself is somewhat arbitrary. In my belief it was originally chosen because it's a round number, off the worst of the toe of the curve, that was fairly easy to determine with the primitive densitometers of the 1930s. Many were comparison densitometers (I have one somewhere) and these are easiest to build and use in discrete steps, with 1/3 stop an obvious step. I don't know when electronic densitometers came in, but I do know that early models tended to drift terribly and required frequent recalibration. Then the 0.10 speed point survived because it's (comparatively) easy to reconcile adequately with the fractional gradient criterion under ISO contrast conditions -- and from what you have said elsewhere, ISO contrast conditions may have been influenced by the need to keep the two speed points (fractional gradient and fixed density) in sight of each other.

 

Sorry for coming in late to this thread, but I've been out taking pictures...

 

Cheers,

 

Roger

Thanks Roger, not only for the much appreciated defense, but for a very thoughtful post. It�s an excellent example of the level of discourse possible and seldom achieved. If more of the posts were even half as good, this could have been an informative thread. However, for me it comes too late. I�m considering ending my participation on these forums all together. It�s just not worth the effort if most of the posts are little more than half assed thoughts and unsubstantiated yet emphatic statements.

 

Maybe I should have posted my thoughts on Sunny 16 at the beginning of the thread and then asked for reactions, but I knew that if I did, there would only be silence. There seems to be only a few people willing to engage in the threads containing anything substantial. Where were all the people complaining about this thread when we were discussing Tone Reproduction Theory? Where were they when we were helping Al DiVenuti define a normal contrast negative? Perhaps we should rename this forum the �How Long Do I Develop This For? Forum�

 

I feel I should post my thoughts on Sunny 16 since I started this mess. Maybe soon.

Yet again, the hand is quicker than the eye - and my index finger quicker than my brain.

 

I said "Like the explanation for why the sky is blue, the "sunny 16" rule is scientifically incorrect, but good enough for everyday use - unless you happen to know better."

 

"Incomplete" would have been a better choise of word - not "incorrect".

 

The "sunny 16" rule is very useful - if you happen to be photographing under the conditions for which it is valid: Clear sky, bright sun, low altitude, around midday, moderate latitude. Since I do most of my photography at 60° north latitude, I find that "Sunny 11" is a better starting point. The sun is never that high in the sky here.

 

Mixing science into the question was at second thought a bad idea. What we have here is an arbitrarily defined unit (ISO), which under certain circumstances happens to tie in nicely with a rather more basic unit (seconds) and a geometrically derived unit (f-stop).

 

The "Sunny 16" rule is only that: A rule. So the only "proof" will be to use it and see if it works. I happen to have convinced myself that it works, under certain given circumstances. But I'm also aware of all the corrections you may have to do to use it as a basis for exposure under other circumstances...

 

The blueness of the sky is an entirely different matter, as all the variables are clearly defined. That makes it amenable to scientific investigation, unlike exposure rules based in the film's sensitivity to "average" light under "normal" conditions expressed in an arbitrary unit.

I'm a little amazed by all this but not much.

 

Long ago before light meters photographers kept little cheat sheets which would give them exposure under different conditions. This coupled with expierence gained from taking photographs likely led to the Sunny 16. Of course Kodak likely tested it like they used to test everything. It wouldn't suprise me if they published a paper to prove that the sun really is a constant light source.

 

A couple of facts:

 

The sun is a fairly constant light source. Putting out some many foot candles.

 

You can train yourself to judge the differences between the suns light output at "sunny" and the various other times.

 

How does a meter work? It knows so many foot candles equals a certain EV.

 

All sunny 16 does is replace the meter sensor with the grey thing between your ears.

And then after you get an amount of exposure, the development time must be correct for THAT exposure to get the contrast and density you desire, Fun isn't it?

<i> There seems to be only a few people willing to engage in the

threads containing anything substantial. Where were all the

people complaining about this thread when we were discussing

Tone Reproduction Theory? Where were they when we were

helping Al DiVenuti define a normal contrast negative?</i><P>

I think the problem you encountered in this thread is because it

slipped from the substantial (like the two threads you mention

above) to the pedantic. The answers to your questions were (as

Roger demonstrated) straightforward derivations from

information that you obviously already know and simple physical

facts. When you discuss topics that many photographers (even

experienced ones) have only a passing familiarity with, people

can learn something substantial. Reevaluating Sunny 16 strikes

me as being more akin to reevaluating "the area of a rectangle

equals height times width."

Mike, I understand your point and it is well made.

<p>

<i>Reevaluating Sunny 16 strikes me as being more akin to reevaluating "the area of a rectangle equals height times width.</i>

<p>

Maybe you'll change your mind when I post my perspective at a later time. While Roger was lucky enough to be occupied with shooting, I have a rather more mundane and way less enviable task before I can address this question. In effect Mike, you also kind of reiterated my original point. Sometimes we should reevaluate things we think we really know, but I don't want to go down that road again.

<p>

On the topic of "trolling," I wasn't. I believe I was up front. In the original post I said:

<p>

<i>I feel much can be learned by reevaluating these basic rules of photography <u>from a more experienced perspective.</i></u>

<p>

I made this post for three reasons: I love photography and like to discuss topics, I believed I might be able to teach something, I had the opportunity to learn how people perceived the concept.

<p>

It's been my pleasure to meet through this forum people who are very knowledgeable on many different topics? I think there is a common tendency that once you reach a certain point in any field of specialized focus, there is the tendency to lose a general perspective on the subject. You can lose the abiltiy to see how the "average" person see it. Sometimes, you just need a reminder. I know I'm not expressing this well.

<p>

I believe this is the case in a thread that Roger Hicks initiated on 12% or 18% gray. I believe he was only attempting to gain a perspective on how other people saw it. I believe it was an honest attempt for him to reconnect with the topic. As teacher and author, Roger needs to stay in touch with how his students and readers think in order to better convey his knowledge. He wasn't "trolling," but those on that thread tore into him unmercifully.

<p>

In both cases, Roger and I were looking for information from the forum, just not the usual type.

For four generations a family made Thanksgiving stuffing in two pans. When asked why, the answer was always, "That's how I learned it and that's how we've always done it". It turns out that early on, Great Great Grandma's bigger pan would not fit in her small oven so she had to use two smaller pans that would fit. Somewhere along the line, this reason was lost but not the practice. It's OK to question things once in a while even if we've always done them. In the case of sunny 16, we might even learn something useful in the course of a respectful discussion.

 

I do not know the precise sensitometry behind the sunny 16 "rule" but it seems that it must have been derived in order to include the film speed in the rule and is based on the relative consistancy of the sun's midday light output, geography notwithstanding. This is pure speculation on my part. The favorably coincidental poetic alliteration of ssssunny ssssssixteen makes this "rule" even more memorable. Perhaps it persists for this reason as much or more than its actual usefulness.

I've been in bed with the flu for 3 days and haven't looked much at the forums 'til now.

 

Now I feel like I need some mental floss.

Sunny sixteen works because the guys who came up with the numbers that

describe film speeds said, "let's make the film speed the reciprocal of the

shutter speed at f/16 on a sunny day!" And so they did, thereby allowing us to

discover the rule of thumb and wonder why it works.

An "as is no return; Parts only" Ebay camera arrived today; with its Selenium meter on the body. I went outside about 5:30pm; and aimed the dead camera at normal scene; and got only a Sunny F11 . The camera is from 1955. Should I worry? Should I leave positive feedback? The meter was listed as not working; and it is maybe 1 stop off.....Maybe tommorow I will check it under better sunlight; and be able to sleep easier. Maybe it is dead on?

Sunny 16 stops working at 2pm. You need to compensate-)

The density of film is affected by exposure and development. With development constant, it is affected by exposure. Exposure is a product of illumination and the length of time that illumination is allowed to fall on the film. One could say that the speed of a film is the inverse of the number of meter candles with a particular duration required to produce a particular density with a particular development.

 

The average illumination due to sunlight in the temperate zone is a known quantity, and it can be determined that that quantity will produce sufficient illumination on a photographic plate or film at a relative aperture of f/16 to expose the film properly with a duration of 1/ISO. The aperture could have been any other that fit the equation. It is not arbitrary. It need not have been arrived at by trial and error. It can be arrived at by controlled experiment and measurement. The fact that it only applies strictly to the illumination specified by the ISO speed determination does not make it arbitrary. To the contrary, it makes it systematic.

 

There must also be specification of a range of exposure duration over which the rule will work. It might not work on a film with ISO speed of 0.01 because of reciprocal disagreement.

 

The sunny rule was 11 when I got my first adjustable camera.

I measured it at over 16 last time I checked--by half a stop.

In the 1950,s it was sunny f/11. The Kodak Snapshot dial from 1953 is based on f/11.<div></div>