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style="margin-bottom: 0">When The Meter Says “Go Home?”

Published : 20th October 2003


Anyone know of a site/publication which has photometric data for weird things like moonlight?

I shall be attempting some intervalometer shots later this month of landscapes at night (S16mm - Aaton) and I'm concerned that my Minolta III will just shrug and laugh at me.

Anecdotally, I saw some still photographs of moonlit landscapes where the photographer informed me that they were taken on 400ASA stock with exposure times of approx 15mins.

They looked like broad flat daylight. Naturally I shall be on 7279.

Yours,

Tom Townend,
Cinematographer/London.



That well known American, Ansel Adams would rate the moon at about 250 c/ft^2.

How about setting your film speed (high) / exposure time (long) on your meter to give a useable stop and work back from there ?

Jon Mitchell

Elstree UK Based Focus Puller



I have shot moon rises with my e-shot intervalometer at 1/4 of a second exposure, at a T4.0 rating 74 straight at 200. On a clear night it is surprising how bright the moon is (reflected 5.6-8.0s at 200).

Good luck.

Dennis Boni
DP/Steadicam Owner/Op.
IA 600



>Anyone know of a site/publication which has photometric data for weird >things like moonlight?

All I can offer now is this vague anecdote from the quite interesting and extensive but certainly not guaranteed accurate "History of Light and Lighting" Take a look at http://www.mts.net/~william5/history/hol.htm

"The illumination from the sun on the earth's surface can exceed 100,000 LUX, (or 10,000 FC) during a summer day. At night the reflected light from the moon might be as high as 0.2 LUX, (or .002 FC)."

Of course, I add the standard CML acronym, TTT! By the way, remember to tap the 'phase' button to sync to the moon.

Best,
Alan Jacobsen
DP/Gaffer - NYC



The moon is really a credit to our eyes more than anything. Imagine if you filled up every space of the night sky with moons one next to each other until the entire arc of the sky was filled with moons which in my head should be a little over 100,000 moons. With all those moons, you'd think it would be pretty bright right? Even then you'd only get about 1/4 of the suns intensity. Technically the average full moon 464,000 times fainter than a typical sunny day. Take a sheet of clean white paper and stick it out in front of you and what you'll be seeing is a piece of paper that is 2000 fainter than black velvet would be if you held it up in sunlight. Don't worry about the differences in distance of the moon from the earth and sun at different times of the year, it's intensity is considered constant because those distances aren't enough to really make a difference.

The moon reflects about 7% of light hitting it on average, but because the moon is not uniform in tone (it's got all those cliffs and valleys), a quarter phase moon is not half as bright as a full moon, it's actually about a 10th as bright, while about three days prior to a full moon it is equivalent in brightness to half of what that full moon will be three days later. Remember that because the moon is a sphere, it is brighter in the middle than it is on the edges. Plus it is important to keep in mind that less atmosphere will affect your moon sharpness in the dead of winter than a summer night. If this all sounds confusing it should.

The point is to test before you shoot. While there are charts for exposure ranges, the best exposures are determined by you while testing as many variations can alter the quality of your images.

Walter Graff
NYC



Tom Townend writes :

>That well known American, Ansel Adams would rate the moon at about >250 c/ft^2.

Careful, many people interpret that as footcandles, which it isn't. It's candles per sq. ft.

As an illustration of how easy it is to make a mistake, Adams himself used this calculation when taking what is arguably one of the greatest photographs ever "Moonrise - Hernandez, New Mexico." He made a mistake in the calculation and ended up underexposing the shot a full stop.

He saved it with intensifier in the darkroom. Ironic that it is not only a great photo but a perfect example of subtle gradations of grey values - sometimes cited as a "perfectly exposed" photograph by the master himself.

My father lives just up the road from Hernandez and I sometimes stop and take a photo at that same spot, but now the church is surrounded by houses, garages, junked cars, etc. Too bad.

Blain
LA



Tom Townend asked :

>Anyone know of a site/publication which has photometric data for weird >things like moonlight?

The Kodak website has information about astrophotography, including exposure tables:

http://www.kodak.com/cluster/global/en/consumer/products/

techInfo/p150/p150a.shtml

John Pytlak
EI Worldwide Technical Services
Research Labs, Building 69
Eastman Kodak Company
Rochester, New York 14650-1922 USA
website : http://www.kodak.com/go/motion



Hi Tom,

I've mentioned this before on this list, but this is what had worked for me :

Shooting with 5279, I exposed every frame at 30 seconds with f/2 on the lens. With a FULL moon on a CLEAR night, that put my printer lights at a very healthy mid to low 40s. This formula will work well with a half moon at a partly cloudy night.

On full overcast, you will see an interesting texture to the sky, depending on the thickness of the clouds. The Minolta footcandle meter reads to 0.001 fc, does it not?

Cheers,

Duraid Munajim



Duraid Munajim wrote :

>With 5279, I exposed every frame at 30 seconds with f/2 on the lens.

Thanks to everyone who has posted a response to this.

I'm currently sifting through all the leads! However the feat I'm trying to accomplish is not so much the exposure of the moon itself or indeed the night sky so much as a landscape view illuminated by moonlight only. I'm assuming that the above stop & frame rate was provided with that in mind.

Thanks again for the info. A stills test is imminent.

Yours,

Tom Townend,
Cinematographer/London.