FWIW...Sunny whatever!

Arvee · Aug 12, 2008

Been on an extreme retro kick and decided to leave the meters at home for a while. Bein' brave. Sunny 16 should work just fine here in UT where summer is blazing and we have deep blue skies with lots of white poofies, courtesy of the monsoon up from AZ.

After several weeks I noticed that my negs weren't printing up to snuff (too dense) and thought maybe my thermometer had gone south. Nope. Maybe too zealous in my agitation during development? Nope. Perhaps a change in chemistry that caused overdevelopment? Nope. Film problem? Nope. Cockpit error? Yep!

Finally got out my trusty illuminometer and checked ambient outdoor lighting. A normal, bright sunny day is usually 10,000 foot candles, which is sunny 16 on the money. Sure enough, a sunny day in UT at 5K feet elevation is a bit more than a sunny day elsewhere. Meter read 15,460 foot candles, a full 2/3 of a stop brighter than the 'rule.' Makes for burly negs.

Just goes to show you that all those magic rules of thumb do have exceptions sometimes. Sunny 11 in the UK, sunny 11.5 on the East Coast, and I'll bet Denver breaks over the top too.

Anyway, FWIW, don't overlook the obvious like I did!

-Fred

Mike Wilde · Aug 12, 2008

Yep, that air does filter things.

More seriously, I use some tables that I have distilled out of fredparker.com - the ultimate exposure calculator.

I do quite well with a look at the light, a peek at the table, cross reference to the speed of film, jump the right number of steps for any filter factor, and the results are really good.

I like going this way with any old camera built without a meter. I have a slowly evolving collection of older cameras. I usually clean them up, shoot at least one roll successfully in them and then put them on the shelf in the family room until the next urge to shoot with it comes along. I process the roll, contact print it, and then print up a couple of respectable negatives, and put them all in a transparent sleeve that gets displayed behind the camera. Then when someone wanders in and says something like 'oh look at the old cameras' I am able to show that it is more the photographer than the latest camera that is needed to make a nice image.

Stephen Benskin · Aug 12, 2008

Fred,

Excellent observation. If you're interested in exploring the topic further, there is a rather long tedious two part article on the subject. Loyd Jones at some point in the, I believe, 80 page article discusses atmospheric pressure and its affects on illuminance. It also covers humidity, which is also a factor (Utah having very little), and latitude. The paper is Jones, Loyd A., Condit, H.R., Sunlight and Skylight as Determinants of Photographic Exposure. I. Luminous Density as Determined by Solar Altitude and Atmospheric Conditions, Journal of the Optical Society of America, V.38 N. 1, Feb 1948. The second part appears one year later.

This is a seminal paper on illuminance. The exposure charts from the paper were later made into an ANSI standard Exposure Guide. Sorry, I can't remember the exact name and ANSI number. I keep misplacing the guide because it's really small (so that it fits in a pocket when out shooting).

Also, don't forget that the illuminance reading results depends on where the meter is aimed. I believe the total illuminance of 10,200 is found when the meter is directed pointed at the sun. When the meter is held at a 41 degree angle from the sun, the illuminance should read around 7680, which is what the average exposure (see Sunny 16) is based upon.

Steve

Christopher Walrath · Aug 12, 2008

Don't have to worry about that too much here in Delaware where the highest point of elevation is the damn fox that just dug a den in the field out back. AGAIN!

nsouto · Aug 13, 2008

Here in Australia, I've found sunny-16 holds true inland, in the deserts.
Where the atmosphere is almost always clear and with no haze.
Nearer the coast, it's sunny-f11 all the way. Haze being the main diference.

Which brings me to my youth, when I was told: "sunny-f11".
I was living near the sea back then.

Maybe there is a pattern somewhere in all that?...
:confused:

Steve Smith · Aug 13, 2008

Fred Aspen said:
Sunny 11 in the UK

I think we're at sunny f2.8 at the moment!

Steve.

Stephen Benskin · Aug 13, 2008

Steve Smith said:
I think we're at sunny f2.8 at the moment!

Steve.

You must be in Beijing then. With that smog, it's magic hour all day long.

Arvee · Aug 13, 2008

Thanks, Stephen, for the reference to the article. It would definitely be of interest. It's protected, however, and there is a fee for purchase.

Based on the information that you provided about the 41 degree angle with respect to the sun, I am virtually at 'Sunny 22' for our atmospheric conditions, a stop over the norm. Explains a lot!

I plan to do a bit more analysis with my light meter in 'light' of this new information. I suspect some interpolation may be necessary.

Is there another site to gain public access to the paper?

-Fred

r-brian · Aug 13, 2008

I've read somewhere that the "Sunny f16 Rule" for high altitudes is really the "Sunny f22 Rule". Living here in Albuquerque, where my house sits at 5200', I shoot from 5200' to 10,600' regularly. Sunny f22 it is for me.

Arvee · Aug 13, 2008

R-brian,

If you happen to remember where you saw that information, I would be interested in reading it. I'm at 5100 base and photograph up from there so I have the same conditions. I will be using sunny F/22 henceforth. Thanks!

-Fred

Dave Miller · Aug 13, 2008

It's sunny 2.8 here at the moment.

Stephen Benskin · Aug 13, 2008

Fred,

I get everything from the local university. Lots cheaper. Just remember to bring a pocket full of change.

Steve

panastasia · Aug 13, 2008

Global dimming (dimming sun), a newly discovered phenomenon, will change this rule-of-thumb. It's believed that the air pollution causing the effect is keeping global warming in check.

FWIW...Sunny whatever!

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