stability of 'sunny 16'

[Alan Edward Klein]

When I studied photography, many, many years ago, we were taught "if in doubt, bracket. Film is cheap, client's time is not".

I barekt when shooting 6x7 (120 film) but not with 4x5.

 

[Alan Edward Klein]

Couple days ago the sun went sunny 11 on me. It's back to sunny 16 now. I don't know what happened. There was no cloud or anything like that that day.

Smog?

 

[Alan Edward Klein]

Don't see why higher altitudes should read less light intensity but all my 'sunny 18' readings were taken at ground level.

Dust and smog make for thicker atmospheres..

 

[Chan Tran]

Smog?

Could be because the light has been quite consistently LV14.7 but that day it was 13.7. I was surprised so much that I pulled out all of my meters and they all agreed that it was sunny 11.

 

[runswithsizzers]

Don't see why higher altitudes should read less light intensity but all my 'sunny 18' readings were taken at ground level.

My post mentioned only latitude, not altitude. Perhaps you meant to reply to @Craig?

I do agree with you -- if anything, I would guess there would be more light at higher elevations, not less. Presumably, the atmosphere itself -- or water vapor, dust, pollutants, etc. which are suspended in the atmosphere -- do block or scatter some light before it reaches the surface.

Here in southern Missouri, our elevation is only about 1100 ft (335 meters) above sea level, so altitude is probably not having much effect. But I am a little surprised that my meter readings taken here at slightly above 37* N latitude seem to agree more with those reported from above 50* latitude as Sunny 11, not Sunny 16.

Then again, when trying to apply the Sunny 16 in the real world, oftentimes one must start with an approximation. For example, I often shoot ISO 400 film, but none of my cameras offer a shutter speed of 1/400. Then there are all the "ifs, ands, and buts" with reguard to the time of day, the season, the latitude, degree of haze, etc. So no point in trying to be too precise about it.

If at all possible, it saves me time and effort to just use my hand-held light meter and take an incident reading. And if my incident meter quits, then I can pull out my smart phone and take a reflected reading using a light meter app. Only if my smart phone also quits, will I ever consider using Sunny 16, or more specifically, Sunny 11, for me.

 

[Chan Tran]

My post mentioned only latitude, not altitude. Perhaps you meant to reply to @Craig?

I do agree with you -- if anything, I would guess there would be more light at higher elevations, not less. Presumably, the atmosphere itself -- or water vapor, dust, pollutants, etc. which are suspended in the atmosphere -- do block or scatter some light before it reaches the surface.

Here in southern Missouri, our elevation is only about 1100 ft (335 meters) above sea level, so altitude is probably not having much effect. But I am a little surprised that my few meter readings taken here at slightly above 37* N latitude seem to agree more with those reported from above 50* latitude.

Then again, when trying to apply the Sunny 16 in the real world, oftentimes one must start with an approximation. For example, I often shoot ISO 400 film, but none of my cameras offer a shutter speed of 1/400. Then there are all the "ifs, ands, and buts" with reguard to the time of day, the season, the latitude, degree of haze, etc. So no point in try to be too precise about it.

If at all possible, it saves me time and effort to just use my hand-held light meter and take an incident reading. And if my incident meter quits, then I can pull out my smart phone and take a reflected reading using a light meter app. Only if my smart phone also quits, will I ever consider using Sunny 16, or more specifically, Sunny 11, for me.

If you shoot ISO 400 you don't have to shoot f/16@1/400. You can use any combinations of aperture and shutter speed that is EV 16 and 1/3. While you shutter speed is only in full stop you can set the aperture between stops can't you? For example with ISO400 film you can do 1/1000 and f/10 which is 1/3 stop larger than f/11.

 

[runswithsizzers]

If you shoot ISO 400 you don't have to shoot f/16@1/400. You can use any combinations of aperture and shutter speed that is EV 16 and 1/3. While you shutter speed is only in full stop you can set the aperture between stops can't you? For example with ISO400 film you can do 1/1000 and f/10 which is 1/3 stop larger than f/11.

Yes, all true. I suppose if I practiced enough, all the necessary mental calculations would become easier -- possibly even second nature. But lacking that familiarity, these mental gymnastics get in the way and turn a fun activity (taking photos) into a chore.

For example, if the correct exposure is 1/400 sec at f/16, then what aperture gives the same exposure at 1/500 sec? The solution is not immediately clear to me.

In your example, you say, "with ISO400 film you can do 1/1000 and f/10 which is 1/3 stop larger than f/11" but how did you get from "1/400th sec at f/16" to "1/1000th at f/10"?

There was a brief period in my life when I could solve a quadratic equation with a pencil and paper. But once I discovered how do it with my scientific calculator, I did not see any virtue in continuing to do it the hard way. (Today, I've forgotten how to work the calculator, but one needs to solve a quadratic equation so rarely these days... ;-)

I hope I may be forgiven for any moral weakness if I just take the easy way out (for me) and resort to using one of my light meters. I realize this strategy leaves me hopelessly unprepared for the zombie apocalypse during which time batteries may become unavailable. But by then, I expect we will have other concerns more demanding of our attention than taking photos and solving quadratic equations.

 

[Chan Tran]

Yes, all true. I suppose if I practiced enough, all the necessary mental calculations would become easier -- possibly even second nature. But lacking that familiarity, these mental gymnastics get in the way and turn a fun activity (taking photos) into a chore.

For example, if the correct exposure is 1/400 sec at f/16, then what aperture gives the same exposure at 1/500 sec? The solution is not immediately clear to me.

In your example, you say, "with ISO400 film you can do 1/1000 and f/10 which is 1/3 stop larger than f/11" but how did you get from "1/400th sec at f/16" to "1/1000th at f/10"?

There was a brief period in my life when I could solve a quadratic equation with a pencil and paper. But once I discovered how do it with my scientific calculator, I did not see any virtue in continuing to do it the hard way. (Today, I've forgotten how to work the calculator, but one needs to solve a quadratic equation so rarely these days... ;-)

I hope I may be forgiven for any moral weakness if I just take the easy way out (for me) and resort to using one of my light meters. I realize this strategy leaves me hopelessly unprepared for the zombie apocalypse during which time batteries may become unavailable. But by then, I expect we will have other concerns more demanding of our attention than taking photos and solving quadratic equations.

I made a little mistake. I meant EV16 and 2/3 not 1/3.
You can do it by counting steps.
1. from 1/400 to 1/1000 it's 1 and 1/3 step. 1/3 step from 1/400 to 1/500 and then 1 step from 1/500 to 1/1000.
2. So you open the aperture by the same amount. 1 step larger than 1/16 is f/11 and then another 1/3 step and that's f/10.

However I assign each shutter speed and aperture a value I call them Time Value for the shutter speed and Aperture Value for aperture. So starting with 1 second that TV0 and every stop add 1 to the value. For the AV starting from f/1 and that f/1=AV0. I then learned by heart the value of these. For example 1/1000=TV10, f/16=AV8, 1/400 which is 2/3 stop higher than 1/250 which is TV8 so 1/400 is TV8.7. So the EV=AV8+TV8.7=EV16.7. Now the sunny 16 has the Light Value (LV) of 14.7 that is the EV for ISO 100. So I assign ISO100 the value of 0 and for every stop faster add 1. So ISO 400 has the value of 2 so I add LV14.7+2=EV16.7.
After a while I would remember the values for all the full stop and then I can deduce the 1/3 stops increment rather easily.

 

[MattKing]

I wonder how many advocates of "sunny 11" are also advocates of Zone System based film exposure determinations ?
That pesky 2/3 of a stop .......

 

[Chan Tran]

I wonder how many advocates of "sunny 11" are also advocates of Zone System based film exposure determinations ?
That pesky 2/3 of a stop .......

I think "sunny 11" or "sunny 16" advocates don't use the Zone system. But I may be wrong but my reasons are.
1. The "Sunny 16" rule is based on illuminance that is incident light falling on the subject. The Zone system based on luminance which is light reflected off the subject.
2. The "Sunny 16" is used because one doesn't use a meter and you must have a meter for the Zone system.

 

[MattKing]

I think "sunny 11" or "sunny 16" advocates don't use the Zone system. But I may be wrong but my reasons are.
1. The "Sunny 16" rule is based on illuminance that is incident light falling on the subject. The Zone system based on luminance which is light reflected off the subject.
2. The "Sunny 16" is used because one doesn't use a meter and you must have a meter for the Zone system.

All true.
But it is also true that the Zone System people usually start out with a film sensitivity number ("EI") about 2/3 of a stop slower than the box speed ("ISO") people.

 

[tjwspm]

I checked again today and with nine(9 d)! different meters I get in Cologne,Germany at high noon exactly EV 15.0; remarkable.

Ralph,
thank you for your wonderful idea to check the Sunny 16 rule worldwide, over the times of day and the seasons with the help of this forum.

Like you, I find that the results match amazingly well.

Of course, I would also like to make my contribution - albeit very late.
So today April 14, 2025 at 2:19 pm in Bordeaux, France: EV 14.99 in full sun. Measured with my smartphone app:



Since I shoot a lot with the Minox A, sunny 16 is a cool thing for me. This camera doesn't have a lightmeter and I would find it ridiculous to take an external device with me that is twice as big and heavy as the camera itself.

-Thomas

 

[Craig]

I wonder how many advocates of "sunny 11" are also advocates of Zone System based film exposure determinations ?
That pesky 2/3 of a stop .......

I don't use the zone system. I went through all the gymnastics of determining an exposure, placing values etc etc and I found that I came to the exact same shutter speed/aperture that my Nikon set to matrix metering suggested.

I repeated the experiment a number of times for various scenes with the same results, so I now use whatever Nikon suggests. Seems to work.

Added: The zone system doesn't work for slide film, and I do use that as well.

 

[Craig]

Don't see why higher altitudes should read less light intensity but all my 'sunny 18' readings were taken at ground level.

There is much more atmosphere for the light to pass though at sea level. Humidity will play a role too, that acts like a giant softbox to diffuse and weaken the light intensity. If I'm at 2000m elevation, there is much less atmosphere to filter the light though.

 

[Paul Howell]

With TTL metering even a small gray card is workable as is light skinned hand.

 

[Sirius Glass]

With TTL metering even a small gray card is workable as is light skinned hand.

If one does not have light skin, use the palm of the hand instead.

 

[tjwspm]

my dear friends on APUG,
I need your help for a world-wide experiment.the sun is known to be an extremely stable light source and has been for he last 4.5 billion yearswith promise to do the same for another 4.5 billion yearson a clear sunny day, it provides bout 82klux,measured on a perpendicular(normal)plane to the sun.this can be measured with an incident lightmetercapable of eadind in EVsat 100ISO,atich it should read EV 15.I have done this in Northern Europe and in North Amrikaand never had more than a 0.1 deviation from 15EV .Let's see how stable this is world-wide.Please take your incident meters,meters,step outside,point the dome directly into the sun and take an EV reading. Then please report it here with your location.I'll start:Florida, USA,yesterday3pmEV15.1;today11am14.9EV.
tanks for the effort

Today May 11, 2025 at 10:57 am in Baesweiler, Germany: EV 14.58 in full sun. Measured with my smartphone app:

 

[DREW WILEY]

How does "sunny 16" work on the moon? My wife attended an astronaut's funeral a few weeks ago (a former patient of hers). But he had been in charge of guidance systems and ergonomics training for the Apollo missions, and didn't know a lot about the cameras on those missions.

Let's see what the typical advice here might have been like. "Earthrise" picture during orbit around the moon : Walk back to earth and take an incident meter reading; return to moon; try to figure out which Zones the shadow values on the lunar craters fall on - wait a minute - shadows fall in two different directions! Cry for help, and then suddenly out of nowhere both Minor White and Timothy Leary show up from outer space at the same time, and give you the answer!
Then Elon Musk defunds your flight back.

 

[BrianShaw]

Today May 11, 2025 at 10:57 am in Baesweiler, Germany: EV 14.58 in full sun. Measured with my smartphone app:

View attachment 398310

What was your altitude?

 

[BrianShaw]

@drew. Why bother with sunny-anything when you have one of these:

Spotmeter, 1 Degree, Automatic, Apollo 11 | National Air and Space Museum

airandspace.si.edu

 

[DREW WILEY]

That's really cool, Brian. Thanks. I've handled sample modern space cordless screwdrivers; a bit pricey, to say the least.

What I can't figure out is that alleged Smartphone reading on the previous post. With Minolta and Pentax real spot meters, 14-1/2 EV is just a stop and a half above a typical sunny day midtone reading. Maybe that cellphone just went daffy due to being "blinded" by a direct sun reading. Or else its averaging in everything else in some schizophrenic manner.

 

[BrianShaw]

Please don’t omit Sekonic from the list of “real” spot meters. I want to be part of the “real” club too.

 

[Chan Tran]

That's really cool, Brian. Thanks. I've handled sample modern space cordless screwdrivers; a bit pricey, to say the least.

What I can't figure out is that alleged Smartphone reading on the previous post. With Minolta and Pentax real spot meters, 14-1/2 EV is just a stop and a half above a typical sunny day midtone reading. Maybe that cellphone just went daffy due to being "blinded" by a direct sun reading. Or else its averaging in everything else in some schizophrenic manner.

I believe the phone took an incident reading as it displays the illuminance in Lux.

 

[wiltw]

I can imagine explaining to your subject how to hold the card thus in front of her/his face while you take a reading. Is that the one third nearer to the camera, a or the third nearer to the light source?

Angle zero degees is 'at the lens' so, one-third of angle moves the card 33% of the way from the lens, toward the sun (source).

 

[tjwspm]

What was your altitude?

138 m

What I can't figure out is that alleged Smartphone reading on the previous post. With Minolta and Pentax real spot meters, 14-1/2 EV is just a stop and a half above a typical sunny day midtone reading. Maybe that cellphone just went daffy due to being "blinded" by a direct sun reading. Or else its averaging in everything else in some schizophrenic manner.

With this app and this smartphone, I have been successfully determining the exposure times for Kodak Ektar 100 and my Minox A, Riga Minox and Minox AX for a long time. These cameras do not have their own light meter. You can see from these photos that the app works:

Gallery

Behind the images shown here is the concept of the present. They reflect the brevity, the fleetingness but also the decisiveness of the moment. They don't want to show the beauty of the world, nor the ugliness.

moments-of-now.com

I have nothing to do with the development of this app. But since it works so well for me, I described it here earlier:

Lightmeter app

Historic pre-1960 cameras often do not have a light meter. Or you have a light meter with selenium cells that no longer works. Then you have to determine

moments-of-now.com