Low light: how do I set the right exposure for night moon photos?

The moon can be a complicated subject. It is a very bright subject compared to the rest of the night sky. It is also a moving subject, and it moves fast enough that it can be problematic. Its luminosity changes according to the time of the month. If you want to capture any other element in a scene with the moon, the exposure can become quite complicated.

alternative text

The photo above was taken on November 8, around 7pm … a fairly new moon. It was filmed with a Canon EOS 450D using the Canon EF 100-400 mm L series lens at 400 mm, f / 7.1 and ISO 800 for 1/2 of a second. That exposure time was necessary to expose the clouds enough to create a silhouette of the treetops in the foreground, and not overexpose the moon itself. It was a rather complicated shot, and in the end the part of the crescent was a little overexposed.

Determining which settings to use comes down to perhaps two things. With what I wanted to compose my scene and how much time I had to take the picture. At 400 mm, the movement of the moon across the sky intensifies quite a bit, and at most it takes approximately 0.8-1 seconds before that movement blurs the details. I wanted to expose enough time for the clouds that obscured the moon to be bright enough to show the silhouettes of the treetops. I also wanted to get some light in the dark part (a wish that really pushed him … and I ended up choosing an exposure that was a bit too high in this case, like 1 / 4-1 / 6th of a second it probably would have been better, or maybe ISO 400 instead of ISO 800.)

There is no single correct set of exposure settings that always exposes the moon correctly. Its luminosity depends on a couple of factors, mainly its phase, its position in the sky and what exactly you want to expose (that is, only the moon or the moon with some light from the earth). Here is a base exposure table for digital cameras, assuming an aperture of f / 8, based in part on my experience (keep in mind that the difference between each phase is not exactly a stop, the scale tends to skew a little when arriving to the full moon):

Base Aperture: f/8

ISO  | Crescent | Quarter |   Half  |  Gibbous  | Full Moon |
-------------------------------------------------------------
100  |    1/2   |   1/4   |   1/8   |    1/15   |   1/30    |
200  |    1/4   |   1/8   |   1/15  |    1/30   |   1/60    |
400  |    1/8   |   1/15  |   1/30  |    1/60   |   1/125   |
800  |    1/15  |   1/30  |   1/60  |    1/125  |   1/160   |
1600 |    1/30  |   1/60  |   1/125 |    1/160  |   1/300   |

From that table, it is quite easy to make extrapolations for special scenarios. If you want some light from the earth, you will want to expose for longer. I would say that getting a pinch of earth's brightness requires an exposure of about 0.8-1 second. This often turns off the lighted part of the moon, so it is only really viable with a half moon.

If you want to capture any detail in the foreground, you will generally also want an exposure time of about 1 s for the silhouettes, or more time for anything else (usually, you will want a double exposure … one for the moon, another for the foreground.)

Blue moons, orange crescent moons hung just above the horizon, etc., will be dimmer than a white moon in the middle of the sky. Slightly longer exposures will be needed, perhaps for a stop or two, to compensate. However, when it comes to exposing the full moon, the opposite is usually true … shorter exposures to a point may be necessary.

To capture the full moon with that orange glow near the horizon, you will probably want to use the following:

ISO 200, f / 8, 1 / 40-1 / 50s

Compensate as necessary for any other composition factor.


TO UPDATE:

Recently I have been photographing the moon a lot. After taking numerous shots of the moon, in its growing, medium, gibbous and complete phases, during eclipses and perigee, I think it is important to make a significant note:

The moon does do not follow any
specific pattern, and there are, in
In the end, few rules you can follow
take a good exposure The table
Above is a good baseline, and it can work
as a starting point, but like you
expand your efforts and aim more
dramatic lunar landscapes, exposing the moon
It's like exposing anything else:
You need to have an idea of ​​it.

Below is a link to a small video that I have been working on, a composition of some of my photographs of the moon and time-lapse videos taken in the last six months:

Lunar landscape


UPDATE 2:

Time for another update. Given my work week and the amount of time I have to spend working in my house in one way or another while there is daylight, most of my recent photographs have been of the moon. My previous update is true, however, I have learned other useful knowledge about lunar photography. The moon is a bright white object. Outside its growing phase, it is possible to take the exhibition VERY far without really overexposing it, although it may seem overexposed in the live view of a camera. (Note: the histogram is not particularly useful when photographing the moon, so use it sparingly and only as a basic guide). To demonstrate what is possible with the exposure to the moon, here are some images of the same exposure … an original, and one automatically corrected and one manually tuned in lightroom:

Original Exhibition:
enter the description of the image here

"Auto Tone" in Lightroom:
enter the description of the image here

  • Exhibition -> -0.05
  • Recovery -> 1
  • Fill light -> 50
  • Blacks -> 0

Manually adjusted to get the best detail in Lightroom:
enter the description of the image here

  • Exhibition -> -2
  • Blacks -> 100
  • Contrast -> 50
  • Curves:
    • Highlights -> +51
    • Lights -> -12
    • Darks -> -14
    • Shadows -> -44
  • Sharp -> 78

The original photo was taken as far as I could into the camera, so it appeared as an almost uniform white disk in the live view of my 450D. The Lightroom histogram function that shows overexposure shows the following for the original image above:

enter the description of the image here

From the manually adjusted image, you can see that the only "real" overexposure is a small point just above the Tycho crater (bright spot surrounded by a very light gray, without any detail). Be afraid to push the exposure. It will capture more details, with less noise, and the corrections during further processing are quite simple. While it may not seem like much on the camera, the amount of detail you can extract from a bright white disk can be surprising.