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Wednesday, 08 August 2007


On a side note, I just noticed the data in the 'full moon' row is equivalent to the old 'sunny 16' rule. Many years ago an old photog told me the same sunlight that strikes the earth also strikes the moon. Interesting.

Dear Thomas,

Yup, that's about the size of it.

The moon's actually about half a stop darker than a typical earthly landscape. That's a whole stop darker than middle grey-- it's not a very light object! But under the full moon, you're seeing the surface by directly incident light that backscatters strongly towards us. Brightens things up considerably. Also, no shadows!

You'll also note that the exposure increases rapidly away from full. That's due to a combination of no backscatter, shadows, and the sunlight hitting the moon at a shallower angle.

pax / Ctein


You have broken the code. It is always "sunny" on the Moon (except when it's not).


I have heard that you do not want to use the sunny 16 directly since you don't want the moon middle grey, you want it brighter, so you should overexpose by a stop or stop and 1/2.

(I wonder - since my kids will only see shutter and aperture values in 1/3 - 1/2 stop intervals whether they will ever get the intuitive concepts of a "stop" at all...)

Dear Keith,

The "f/16" rule is an amusing coincidence, but don't get fixated on it. Remember that it is nothing more than a rule for rendering earthly scenes (an overall 13% reflectance) with "normal" tonality; it's not an absolute of photography. Definitely not of astrophotography. (Most embarrassing blunder I ever read was a supposed expert on metering and exposure recommending that people photograph Comet Hale Bopp using the f/16 rule, because it was a sunlit object about as far from the sun as the earth was. A mere three or four orders of magnitude error. I'm sure film latitude would cover it.)

How bright you want the moon in your photo is an aesthetic choice. If you're trying to make a nice telephotograph of the moon that clearly shows lunar detail, rendering it as a "middle grey" (which is a full stop lighter than the moon actually is) might be just the way to go. Maybe even half a stop darker, if you want accurate tones.

If you're looking to render it as a luminous object in the sky, you want to go to longer exposures. But remember that if you're using slide film or digital capture, blowing out your highlights is a bigger risk than losing the shadows. And camera shake and subject movement kill more lunar photos than misexposure.

In any case, you're only going to care about making ONE good photograph of the moon at any given point in the eclipse, so bracket, bracket, bracket!

pax / Ctein

The old photog I mentioned in the earlier post was a real codger, and not above pulling the occasional leg. He once covered LBJ's arrival at the Nashville airport with his trusty Crown Graphic. Standing shoulder to shoulder with the traveling press corp (F's and M3's), he licked his index finger, held it up in the air, turned it about, then reached down and adjusted the camera's aperture. Oddly enough, he had plenty of elbow room after that. He called it "Tennessee windage" and, of course, his photos were excellent.


Liberty Science Center in New Jersey is sponsoring a photography contest for the Aug. 28 lunar eclipse. We welcome all entries. Details can be found here: http://www.lsc.org/getinvolved/eclipse

I live in San Jose, CA and while the lunar eclipse was intercepted by clouds and rain, luckily I'd shot my first lunar eclipse previously in August. The images were shot with my Canon 10D at 300mm, various exposure times... i was up all night! 6 hours and about 1000 photos. I've posted some of the best via the link.


Canon 10D, 300mm, f/5.6, ISO 1600, ~2 sec

Love your blog!

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