Shooting (for) the Moon

Shooting (for) the Moon

Knowing how to shoot the moon requires a solid understanding of how exposures work, or more specifically, knowing the limitations of how cameras see light.  You cannot photograph the moon in a nighttime landscape and expect a good result if you are exposing for a city skyline, for example.  Why is that?  Well, think of the light source for the moon – the sun.  The moon is simply a large reflector with an ash gray surface, reflecting the sun’s light back at us at an intensity comparable to midday light.  In fact, you can use the “Sunny f/16 Rule” to manually set the exposure for a full moon at its brightest.  Understanding how truly bright the moon is and how quickly it moves across the sky are key to knowing when and how to photograph it with a broader landscape.

When is the best time to photograph the moon with the landscape?  The absolute best time is when you can set a single exposure that both correctly exposes for the moon and the landscape.  That means, the best time is when there is some amount of daylight available, usually at the margins of the day.  I have found the best time is to capture a moonrise at or near sunset or a moonset at or near sunrise.  At those times, the exposures necessary to capture the moon without blowing it out (losing the detail in its surface) are about the same as those needed to capture the landscape.  How do you know when this timing occurs?  I regularly use the U.S. Naval Observatory “Complete Sun and Moon Data” web page for this information.  There, you can enter a date and location, by either city name or latitude and longitude, and get complete information as to sunrise and sunset, moonrise and moonset, twilight, and the phase of the moon.  This is also useful for aurora photography, because you want to know if the moon is going to be too bright to capture the aurora.

Now, if it turns out that the exposure time needed for the moon is slightly faster that what you need for your landscape, then simply use a graduated neutral density filter to darken the moon just enough to balance your exposure.

But what about those nighttime exposures?  First, you have to decide whether it is important to capture the detail in the surface of the moon.  If it is not important, and you don’t mind (maybe even want) the moon to be a large glowing orb in the sky, then simply expose for your landscape and click that shutter release button.

But, if you want the moon to be correctly exposed and you want your landscape to be correctly exposed, then you have to take two exposures – one for the moon and one for the landscape – and then merge the two together in Photoshop.  When you do this, however, you will notice that the moon looks really small, particularly if you are shooting a wide angle lens or a panoramic.  The only way to make the moon look big is to really zoom in, typically with a 500mm lens.  But you run the risk of creating a VERY obvious composite if you use that 500mm moon capture and merge it with your landscape that was captured with a 70-200 lens, or even worse, a 500mm moon with a 24mm landscape.  The moon ends up looking unnaturally and ridiculously large.  To see an example, check out the panel of three panoramas below: one with the same exposure for moon and city, one with separate exposures, and one with separate exposures AND different lenses.  Of course, whether it is still “appropriate” to use the composite with the unusually large moon depends on whether you are trying to depict things as they naturally are or as they are perceived.  For the composite example below, it was our 18-year “super” moon, where it is perceived as much larger than a usual full moon due to the closer proximity of the moon.

The other important thing to remember is that the moon is moving faster across the sky than you realize.  This will affect how your exposure looks if you are using a wide angle lens and you are using a longer exposure to capture a dark landscape.  During that exposure, the moon is moving, and burning its light across the sky in your composition.  It will also affect the framing and composition of your image if you are using a long lens, like a 500mm.  If you have a tight crop, the moon will move quickly out of your frame.  To illustrate, check out my multiple exposure below of the lunar eclipse that occurred during the winter solstice last year.  Each image of the moon represents about a 45 second time lapse.

2 Responses to “Shooting (for) the Moon”

  1. Carl Johnson Photography - Blog Says:

    […] or moonset is when they correspond with sunsets or sunrises.  Why?  It is easier to get a balanced exposure – with detail in the landscape as well as the moon – when the moon is rising or setting while […]

  2. Ian Reid Says:

    Excellent well written article on understanding moon photography. thank you for sharing this information, Carl.

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