Correct exposure for the moon?

[wbrook13]

Last week while taking pictures of the Houston skyline, I noticed the moon was coming up behind the buildings, so I wanted to include it in some of the photos. However, with the length of the exposures needed for the rest of the picture, the moon is over-exposed and obviously has moved during exposure.
How do you get the correct exposure for the moon, keeping it sharp, while still getting enough light for the remaining elements in this photo? Or, does it look okay with the moon looking the way it does?
I enjoy taking photos of night time lighting, and would really appreciate any/all techniques you use for night photography.



Camera: Canon EOS 50D
Exposure: 65 seconds
Aperture: f/13.0
Focal Length: 18 mm
ISO Speed: 100
Exposure Bias: 0 EV
Flash: Off, Did not fire

[LeeR]

Interesting you should ask this question today. I was just reading about one of the most loved photographs of all time, certainly one of the most expensive; "Moonrise Hernandez" by Ansel Adams.

As the story goes, Adams couldn't find his light meter when he stumbled across this scene and knew the daylight was disappearing fast. He wondered if he knew the luminance values of anything around and suddenly realized he knew the value for the moon. Based on that, he was able to calculate the exposure, adjust for the filter he was using and hope the shot turned out. He tried to get a second shot but by that time the light hitting the tombstones had vanished so he packed up and headed home with the hope that the first shot would be enough.

So what is the exposure for the moon? We know that it is always daylight on the moon, so some people suggest we just shoot by the old film method we used to call 'sunny 16' (f16 at 1/ISO) that means if you are shooting at 100 ISO you would use an aperture of f16 and a shutter speed of 1/100 of a second anytime you are shooting in braoddaylight. However, there are a number of other factors that need to be considered such as haze and how close the moon is to the horizon. ( Check out Jeff Conrad's excellent site for a more detailed explanation.)
Let's say that after taking everything else into consideration you decide a proper exposure would be f8 at 1/100. Then you remember, no, that would make the moon gray(Zone 5), you want it to be white. Adams choose to place the moon at Zone 7, which meant opening up by two stops to f5.6 at 1/ISO. In many cases this will be the right exposure for the moon, though not all. Might want to bracket if you are driving by Hernandez, NM, when the moon is risiig.

[wbrook13]

So, Lee, that will make the moon look right . . . . . but what about the rest of the scene? Do I have to do something in PSE 7, or Lightroom?

[neoclick]

A lot of folks will blend two exposures in PP to make the moon look more natural.

One pic exposed for the moon, blended with one pic exposed for the foreground. I think they call it moon swapping.

To take it further, the shot that is exposed for the moon can be taken at a different focal length in order to make the moon look bigger. This could be because they simply want the moon to look big, or in the case of a wide angle lens (wide angle can make the background objects look smaller) make the moon look more natural.

[wbrook13]

Okay, thanks. I'll read up on it, and see if it can be done in PSE 7.