Differences in daylight around the world.

[leeturner]

A strange topic title but I couldn't think of a succinct way of describing it.

I spent many years in Southern Africa and my main system was based around 35mm format. I typically used 100/200 ASA film in both colour and b&w and this covered most situations from candid to motorsport photography.

Three years ago I moved back to the UK. Until this weekend I have been taking photographs with tripod mounted medium format gear. I decided to get another 35mm SLR due to my slow reacting eyes and much faster young children.

Anyway, yesterday I went out with the kids, camera and some HP5+. It was a sunny winters day but the difference in exposure, with similiar visible conditions, between the Southern hemisphere and the UK was quite startling. It's really the first time I've noticed it because it's the first time in the UK that I've been handholding a camera. Is it just me or is the sunny16 different in Northern Europe, and does one generally use a faster film when handholding a camera?

[Ole]

I believe in Sunny 11, not 16. But then I'm even further north than you are...

I have experienced that Sunny 16 can work too, but not in Norway. There's a difference between 60 degrees latitude and 10 degrees, where I found to my surprise that 16 was correct.

[Bob F.]

It's December so the sun barely reaches 15 degrees above the horizon at mid-day in London... Even in mid summer, it's at around 60 degrees maximum as opposed to 85 degrees in Johannesburg. I agree with Ole: sunny 11 in winter on the odd halcyon day that it manages to shine is a better bet...

Cheers, Bob.

[philldresser]

Lee

I lived in South Africa for 20 years and definitely noticed a difference in light quality and intensity after returning to the UK. I have never used the sunny 16 rule in anger but definitely had to use faster films when handholding. Not sure if this is right but in winter I put this down to the height of the sun being lower, which means it gets more dispersered along its longer journey through the atmosphere.

It is interesting as my wife also noticed this and she does not have a photographic bone in her body


Looks like Bobs post backs up my theory!!!


Phill

[Nick Zentena]

Sunny 16 requires knowing the light. What most people call sunning is usually hazy which would be F/11.

Plus the rule is only between 10am and 2pm.

You need to read your shadows. The rule goes from F/5.6 to F/22

[leeturner]

Hey Phill, I also lived in S.A. (Durban and Joburg) for 20 years, is it a time limit!

I must admit that, even having been born and raised in the UK, I was surprised by the significant difference in exposure. A couple of times I checked the camera reading against my gossen meter, checked that the film speed was correct etc..

[Ole]

Old photography books (pre-lightmeter) very often have big tables describing exposure as a function of weather, time of day, time of year, and latitude. At 60° the average absorption by the atmosphere is twice what it is at the equator, simply because the light has to pass through twice as much atmosphere.

[Struan Gray]

It's "Gloomy 1.4" season round here. And that's outdoors.

[leeturner]

OT a bit, but with the limited amount of quality daylight around at this time of year, what photography related activities do you do. e.g. catch up on prints, start on some still life, portraits? Or just set sail for sunnier climes.

It very much seems like I'll have to plan my year ahead so that winter will be spent in the darkroom.

[Jim Chinn]

The intensity of light from the sun is constant regardless of where you stand on the globe. "Quality" of light has to do with atmospheric conditions (humidity and natural or man made pollution) and the season. Temperature and color of light also has to do with how the light is filtered by the atmosphere and the amount of humidiity, your altitude, pollution etc.

So you are correct in considering the angle of the Sun in winter. Couple this with what is probably a much more polluted atmosphere over Britain as compared to South Africa and you easily can lose at least one and probably two stops.

It would be interesting to know how much the "quality" of light has changed over the years in places like New Mexico considering the haze from western pollution and humidity introduced by heavy irrigation of farm crops and yards.