Metering night scenes

DBP

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Burn him! Or maybe dodge him?
 

Kilgallb

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This months issue of view camera magazine has an excellent article on just this topic.
 

Early Riser

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I second the opinion about the Calculite XP, I own one and it does read incredibly low light, I believe it goes down to -7EV.
 

walter23

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I find once you get really dark it doesn't matter too much because of reciprocity and the fact that huge increments of time only change your exposure (in EV values) by a bit... eg. if you're in the regime where you need a 15 minute exposure you can pretty much just open up the shutter and walk away for as long as you want and your exposure will probably be almost the same.

I'm talking out in the country doing moonlight, fading twilight, or star trails - in the city you can probably meter with your sekonic just fine.
 
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copake_ham

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Roger Hicks said:
Has anyone yet mentiomed the 'million time sunny 16 rule'? Under a full moon, give 1.000.000x sunny 16. It works -- I've tried it. Bracket an extra stop to allow for reciprocity.

Cheers,

Roger
Click to expand...

Roger,

Would you please explain this "million times sunny rule" a bit further?

If I am shooting film rated at ISO 100 - under the sunny 16 rule I would shoot f16 at 1/125th of a second (and, as you suggest, bracket down to 1/60 and up to 1/250)

Now, a million TIMES 1/125th of a second (if my camera could do it) would be 1/125,000,000th of a second!

My shutter doesn't do that fast! What am I missing?
 

Sirius Glass

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Roger Hicks said:
Has anyone yet mentiomed the 'million time sunny 16 rule'? Under a full moon, give 1.000.000x sunny 16. It works -- I've tried it. Bracket an extra stop to allow for reciprocity.

Cheers,

Roger
Click to expand...

No, no, no!

The Earth and Moon are illuminated by the same source at approximately the same distance.

The albedo on the Moon is 0.5 [reflects 50% of the light that illuminates it].

Therefore the exposure for a Full Moon is 1/ASA shutter speed at f/11 [open one stop for the albedo].

The Moon subtens 0.5 degrees. The Moon moves 15 degrees per hour which is 0.25 degrees per minute therefore to prevent blurring shoot faster that 1/[2 * focal length] for 35mm [example: 1/100 second for a 50mm lens] or 1/focal length for MF [1/100 second for an 80mm lens].

If the phase of the Moon shows less that an full Moon adjust accordingly.

YMMV,
Steve
 

copake_ham

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Paul_C said:
Actually it'd be 1,000,000/125th of a second (a little over 2 hours).
Click to expand...

Smarter than me with the "quick math". Thanks



Much smarther than all of us!

Still trying to fathom a "millon times Sunny/16" as any kind of a "rule"! :rolleyes:
 

Lee L

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Stever said:
No, no, no!
<snip>
YMMV,
Steve
Click to expand...

And your mileage will vary widely if you're talking about taking photos of objects on earth, illuminated by the reflection of sunlight off the moon, which is what Roger is talking about.

Lee
 

copake_ham

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Paul_C said:
Wait, I thought we were exposing for a night scene lit by the moon, not exposing for the moon itself.
Click to expand...

Granted.

But what would you shoot at full moonlight for 2 hours using ISO 100 at 1/125th?

I can see 2 hours as a shot for star trails on a MOONLESS night - but a terrestrial shot for 2 hours in a full moon? :confused:
 

copake_ham

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Paul_C said:
I didn't say I would, I was just correcting the math.
Click to expand...

That makes sense!

Still trying to understand the "million times sunny/16"...
 

Roger Hicks

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Stever said:
No, no, no! . . . Therefore the exposure for a Full Moon is 1/ASA shutter speed at f/11 [open one stop for the albedo].
Click to expand...

Re-read the post. I said 'under' a full moon' not 'of'.

Otherwise I'd not have said that I'd tried it and it worked.

ISO 125 = 1/125th at 16 = 1/1000 at f/5.6. Multiply by 1,000,000 and that's 1000 seconds at f/5.6, or 500 seconds at f/4 or 250 seconds at f/2.8 or 125 seconds at f/2 or 62.5 seconds at f/1.4. Add on a bit for reciprocity and call it 2 minutes.

Actually I tried it with ISO 50 Fuji colour film and it was 5 minutes at f/1.4 -- and, of course, the sky was sky-blue (with very faint star-trails), the shadows looked like sunlight, and all in all it looked like a rather weird shot under sunlight, one where there was something wrong but you couldn't say what. The picture, a portrait of me by Frances, is in one of my books -- I can't remember which one -- and it was in Shutterbug too.

Cheers,

Roger
 
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Roger Hicks

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Steve Smith said:
Yes. You did last month!!!

Steve.
Click to expand...

Dear Steve,

Well, given that some people didn't understand it this time, and I had to explain, maybe it's as well I repeated it.

You'd need to give a VERY long exposure at f/16, of course, but I assumed that most people would work out that you could open up. Also, it's very rare for most people nowadays to find anywhere illuminated only by the night sky, without some form of artificial light to supplement it.

Actually, I think it must have been longer ago than last month because I was away for most of May.

Cheers,

Roger
 

Sirius Glass

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copake_ham said:
That makes sense!

Still trying to understand the "million times sunny/16"...
Click to expand...

* 2

Among other things not quantified:
Are these scenes with or with the Moon?
If they are without the Moon, are they with or without snow?
If they are without the Moon, are they with or without any artifical illumination such as a porch light? What kind? Where?
...

but that still does not explain "million times sunny/16"

Steve
 

Roger Hicks

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Dear Steve,

Which bit don't you understand?

Moonlight? NOT moonlight supplemented by other light, but under a full moon. I could have added 'not supplemented by flash, or Roman candles, or car headlights, or matchlight, or any other damn' form of light,' but that could go on forever. BY THE LIGHT OF A FULL MOON AND NOTHING ELSE EXCEPT STARLIGHT -- which I think most would have understood unless they were trying not to.

The inclusion of the moon is irrelevant, though if it is in shot, you'll get a white sausage if the exposure is long enough.

Snow? Well, most people realize that most guidelines are given for a 'normal' scene, though as this is effectively an incident light rule-of-thumb, it should work pretty well with snow too. You might need to cut exposure by 1/2 stop to get texture in the snow but this is not beyond the wit of man.

I really can't see how much more explanation is needed, but I'll try again:

Shoot at 1,000,000x sunny 16 under a full moon and you'll get a shot with shadow detail. It will be much lighter than the average 'night' shot, because the sky will be sky-blue not black, but you will have about the right amount of light on the subject even with a tranny.

Anything else you need to know about this very simple and easily verified observation?

Cheers,

Roger
 
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Dinesh

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Roger Hicks said:
................ but you will have about the right amount of light on the subject even with a tranny.
Click to expand...

My inner child is dying to make an inappropriate joke here!
 

Sirius Glass

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From the "Jiffy Calculator for Night Exposures" copyright 1964 by S. P. Martin

ASA 100
Scene Description Shutter Speed f/STOP
24 Full-moon, snowscape, and icescape 45 seconds 5.6
25 Full-moon, seascape, and sandscape 60 seconds 5.6
26 full-moon, landscape 90 seconds 5.6


Roger,

Now you see why I wanted clarification of the scene conditions

YMMV,
Steve
 

Roger Hicks

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Dear Steve,

Try mine (which I got from an astrophysicist chum) and his.

Cheers,

Roger
 
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