sunny 16 and geographic location/seasons

[Mike Kennedy]

Have decided to dust off some of my 'ole' beater cameras and rely on the sunny 16 rule for metering.Will my position on the map (eastern Canada) and/or the time of the year (fall,with the sun in a lower arc) effect the rule.Maybe somewhere between f11 and f16?

 

[2F/2F]

The "rule" (Basic Daylight Exposure AKA sunny 16) is a close-enough guideline to get you started, and you are expected to have to adjust until you find out what is working for your conditions. It assumes EV 15 ambient light on a CLEAR and SUNNY day. This is '125 at f/16 using an ISO 100 film. Here in L.A., we don't really have sunny 16 conditions that often, although we tend to think that they are because it is all relative. Unless the day is truly clear, I use f/11 at '125 (or '100 usually, due to the shutter speeds on the cameras) as the baseline.

If you factor in that your shutter might be slightly off and that your developing will likely be a bit different from the film companies', you have even more reason to just shoot some and find out.

Sorry if this is a "bummer" answer. I really don't know about how to alter the rule for different parts of the world. I would just shoot a roll using BDE guidelines and see what happens!

P.S. As Ari just mentioned below, you might find it informative to use a light meter at first, and IMO this is mostly to figure out the pluses or minuses off of BDE for open shade, full shade, cloudy bright, hazy, etc. If it is a reflected meter, I don't think it will help you much unless you also bring a grey card. I recommend a dedicated incident meter, or a reflected meter with a little white bubble, so you measure the over all average level of light, instead of the light reflected off of stuff in the general area of your composition, with the assumption that you want everything to average to a middle grey.

To get a decent meter on the way cheap, look for Brockway meters. They are older versions of Sekonic Studio incident meters that go for next to nothing on E-Bay. They require no batteries, and mine works just fine alongside my spot meter. Gives me the same or within 1/3 stop of my spot meter reading off a grey card. It came with a case, the flat white disc, the dome, the grid, and three slides for $4.99 plus shipping, for a total of 11 or 12 bucks. My model is the "Norwood Director", though there may be others that are similar.

 

[arigram]

The best thing you can do is take some readings with a light meter in different light conditions and seasons and see how close it is to the Sunny16. You may find that you need a take a stop off in your location and just adjust accordingly.
Over here in Greece, Sunny16 is sometimes closer to Sunny22. I imagine in countries further north or south you will have to adjust.

 

[Mike Kennedy]

Two great suggestions.Duly noted.

 

[Steve Smith]

In the UK sunny f11 is usually correct. You're in a similar latitude position so your amount of light may be similar.

I would run a transparency film a various exposures on a bright day and see what you get. Well.... I say " I would" but I haven't - and have no intention of doing that! I find sunny f11 works fine for me most of the time.



Steve.

 

[nsouto]

Actually, I just re-read the original Kodak info on which the "sunny f16" mantra is based.

It recommends f16 only for sunny days, on light sand or snow!
In other words, if one uses it on a sunny day, it will underexpose by one stop...
See Mark's blog for an image of the original recommendation inserted in Kodacolor film ages ago.

And it confirms my own observation:
sunny days, f11, unless I'm at the beach or in the Snowys.

 

[Mike Wilde]

Good online meter by sight resource

look up fred parker - the ultimate exposure computer. I use the tables from the article all the time with good results with older meterless cameras.

 

[wiltw]

Actually, I just re-read the original Kodak info on which the "sunny f16" mantra is based.

It recommends f16 only for sunny days, on light sand or snow!
In other words, if one uses it on a sunny day, it will underexpose by one stop...
See Mark's blog for an image of the original recommendation inserted in Kodacolor film ages ago.

And it confirms my own observation:
sunny days, f11, unless I'm at the beach or in the Snowys.

Sunny 16 is really open for interpretation! I remember it as:

Bright sun on beach or snow Close 1 f /stop
Normal Bright Sun Sunny 16 Rule
Hazy sun, soft shadows Open 1 f /stop
Cloudy bright, no shadows Open 2 f /stops
Open shade, no sun Open 3 f /stops
Heavy overcast Open 3 f /stops

In the 1984 publication, The Users Guide to Photographic Film, it mentions Adjustments to Sunny 16:

"bright or hazy sun on bright sand, snow, or still waters: close down one stop or use next higher shutter speed." This jives with my own recollection.

Ansel Adams himself wrote, in The Negative, about emergency estimation of exposure,
"to refer to the 'tip sheet' packaged with the film...A second approach is...under bright sunlight conditions a 'normal' exposure is about f/16 at a shutter speed equal to 1/ASA-number.

The difference is 'bright sunlight' vs. 'bright sunlight on bright sand, snow'. Numerous reference in print, like John Shaw's Closeups in Nature refer to Sunny 16 and going outside on a bright sunny day and f/16, and snow or beaches is not a pre-req!

 

[removed account4]

sunny 11 works well, in most situations
unless you are near norway ...

 

[Windscale]

One can get by by using Sunny 16 with negatives. But I would suggest the use of a handheld incident light meter for slides. I never leave home without my trusted Sekonic L308.

 

[Stephen Benskin]

THE source comes from a two part paper Loyd Jones wrote in the late 1940s. Jones, Loyd and Condit, H.R., Sunlight and Skylight as Determinants of Photographic Exposure, JOSA, Vol 38 N. 2, 1948 and Vol 39 N.2, 1949. The incredibly tedious study has been condensed down into a usable booklet by ANSI: Photographic Exposure Guide, ANSI PH2.7 - 1986. It's said that if you use the guide properly and it doesn't agree with your meter, then your meter is wrong.

 

[PanaDP]

If you're shooting negative film it will be good enough to get you a reasonably printable image.

I don't know what it would be there. I know that in the summer here in LA, in full sun it's an alarmingly accurate rule. Where my Dad lives at about 5,000 feet in Utah, you'd be better off with a sunny-22 exposure.

 

[rmolson]

Sunny 16


I was shooting one day in a park when the battery in my camera meter died. I was in a complete state of advanced anxiety, when I remembered Hey you spent 9 years as a Navy photographer and did not go around carrying a meter outside. They taught you the basic sunny 16 rule the second day in photo school and it still works !

 

[Stephen Benskin]

I've attached a page from the ANSI Exposure Guide. It has the average Ev for the time of day in each month for a given latitude. Other sections of the book have the various conditions to subtract from the average Ev. In the back is a nomograph to calculate the final camera exposure.

 

[Polybun]

On a side note, in portland we use the sunny 1/16th rule. It will be sunny outside 1/16th of the time! Infact, i think we consider it sunny if we can get F8

 

[Ian Grant]

Here in Turkey the Sunny 1/16th rule means 1/16th of the daylight hours in a year may not be sunny and the brightness at or close to the maximum reading of a Gossen meter

Ian

 

[Polybun]

Here in Turkey the Sunny 1/16th rule means 1/16th of the daylight hours in a year may not be sunny and the brightness at or close to the maximum reading of a Gossen meter

Ian

I need to see turkey. Actually no, really, I do. Its funny when I travel though, I always want to go see the machine shops in town. Locals always seem impressed that I am a tradesman for a living, and have the scars to prove it. Oh, and the chance of steam driven rail roads is attracting as well.

 

[Ole]

It's "sunny 11-ish" here most of the year. This time of year it's more like "sunny wideopen-ish", except that it's rarely sunny.

One of my old German texbooks mentions "die schlechte Monaten" (the bad months) December and January, and recommends that you just forget about photography in those months.

 

[Claire Senft]

The fall of the year can have very brilliant light at the times of the day with the highest illumination. I wish I were I so fortunate as to be in eastern Canada at this time of the year. During the hours of peak illumination and with SNOW on the ground it can well be that sunny 16 rule understates the exposure.

Inspite of all of the marvels in exposure meters and auto exposure nothing is quite so handy as is having a good resevoir of experience to use.

If you are using a camera where the cost of the film is not overly dear to you and the film is of a negative variety then set yourself up a method for bracket. For instance negative 1 sunny 16, negative 2 an additional stop of exposure, negative 3 give 1/2 stop less exposure than sunny 16...
this is said expecting fully illuminated frontly lit subjects.

 

[Anscojohn]

Have decided to dust off some of my 'ole' beater cameras and rely on the sunny 16 rule for metering.Will my position on the map (eastern Canada) and/or the time of the year (fall,with the sun in a lower arc) effect the rule.Maybe somewhere between f11 and f16?

******
Does the sun actually shine in Eastern Canada between summers?

 

[Stephen Benskin]

Here's a bit of a breakdown of Sunny 16. There are two parts. The first uses what is known as the calibration formula for light meters.

A^2/T = B*S/K

Where
A = f/number
T = shutter speed
B = luminance in footlamberts
S = Film speed
K = Constant for reflected light meters (light loss factor)

If you do the Sunny 16 as 1/ISO which means the shutter speed for an ISO 125 speed film would be 1/125. In the calibration formula, that would cancel out T and S, so you are left with:

A^2 = B/K

K is the light loss factor from such things as lens reflection, refractance, lens barrow length, degree of off-axis, etc. This value is considered to be 1.16. B is considered to be 297.

297/1.16 = 256

Plug in f/16 from Sunny 16 and you get 16^2 or 256. The equations are now equal. So for the average luminance of 297 footlamberts for the mid-tone, f/16 at 1/ISO would place the value where the light meter would place it.

The second part is about the value the light meter wants to produce. No matter what, the light meter wants to produce a value of 8 mc entering the camera. The desired exposure for a given film speed is then determined by the shutter speed and f/stop combination. The value of 8 is a photographic constant depicted by the letter "P" (I've found 8.11 to be more accurate). This makes the basic exposure equation E*t = H or in our case for the more specific mid-tone exposure Eg * t = Hg.

I've attached a more detailed illustration of the equations. In effect, the basic exposure equation for the mid-tone exposure is 8*t = Hg. The equation to calculate the mid-tone exposure for a given film speed is:

8/ISO = Hg

so for an ISO 125 film

8/125 = 0.064 meter candle seconds

We've now briefly looked at why f/16 is used and how the average luminance relates to shutter speed and the ISO. So given the average luminance for a sunny day, the camera will produce a value of 8 mc at f/16. If you set your shutter to 1/ISO, the exposure theoretically will the value at the same point as an exposure meter.

This is just a little bit of fun for those interested in going a little deeper into the subject. Even more can be found in:

Connelly, D., Calibration Levels of Films and Exposure Devices, Journal of Photographic Sciences, V. 16, 1968.

 

[Arvee]

Thanks, Stephen, for the chart! It confirms what I have thought for some time but didn't have the data to back it up.

Very helpful information!

-Fred