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Experience with Sunny 16

I too have seen inconsistency with the sunny 16 rule in South Georgia. It's mainly sunny 11 dropping to 8. I just attributed it to varying levels of hazyness; humidty, pollen, and polution along with composition. There have been many times when I thought the meter was underestimating the amout of light on a seemingly sunny day but in most cases the meters were right and my eyes were wrong. Gotta get better at reading the shadows and color lightness I guess.
 
Don't worry. I'm going to get the sun re-calibrated on Thursday.


Steve,
 
Good morning, Steve Smith;

Thank you for the information that the sun will be recalibrated this coming Thursday. I was beginning to worry about that. After all, the Johnson Curve was done back in 1948, and that data is at least 64 years old now.

And all of this time I have been using the "Sunny 16 Rule" without any thought at all to the accuracy of the spectral intensity of the light source.

Actually, the main thing that has been providing problems out here in Latte Land is the correction factor to apply as a function of the varying transmission characteristics of the different types of di-hydrogen oxide units floating in the air above us almost all of the time.
 
The rising cost of fuel will cause the recalibration to occur twice a week Sunday and Wednesday.
 
the sunny 16 rule is just a rule of thumb and, like alan says, really only for 10 am to 2 pm on summer days -- and your experience here in the Rockies also makes sense -- we're about a mile up here, the air is thinner so there's less light lost to the air -- and here in Utah I usually allow an f-stop to the rule because the thinner air means shadows are a bit darker/contrasty because there's less air to reflect light into the shadow areas.

Incident meter is your friend in all cases. Next best tool the human eyeball and the ability to bracket.
 
I sometimes use a Johnson's Exposure Disc. It takes the time, date, scene and weather into account and is surprisingly accurate.


Steve.
 
Sunny 16 used to work fine for me here in Devon, as long as there weren't many clouds. If it was Sunny with clouds, I went for Sunny 11, normally relying on exposure latitude. I don't need to do that anymore now though, seeing as I got a Sekonic L-8 meter. It's extremely reliable, and dead accurate. Highly recommeded for fast, easy, and accurate metering. There's also a free PDF Manual knocking about in the depths of the internet.
 
I remember when Verichrome Pan started showing up marked asa64,over time it magically became asa125. But the film still worked very well at asa64. This film was coated with three emulsions, like Tri-X, and very flexible.:munch:
 
Wow, that's a trip down memory lane, Unfortunately I'm old enough to have bought one of these new, it must be about forty years since Johnsons stopped making them .
 
pentaxuser said:
That inconsistency was extremely dangerous as well. He was called Joseph Stalin or is that the other South Georgia

pentaxuser
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Or is it the South Georgia in the South Atlantic ?
 
Steve Smith said:
I sometimes use a Johnson's Exposure Disc.

It takes the time, date, scene and weather into account and is surprisingly accurate.


Steve.
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A pity that these exposure discs or a copy aren't available anymore. The Black Cat guides seem to be aimed at colour reversal films and digital cameras rather than B&W negative films.
 
Keith Tapscott. said:
A pity that these exposure discs or a copy aren't available anymore. The Black Cat guides seem to be aimed at colour reversal films and digital cameras rather than B&W negative films.
Click to expand...

You can use this text version of how mine works:




Steve.
 
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