Moon Exposure Calculator
Moon exposure is the shutter speed that correctly exposes the moon's surface — and it follows a fixed rule, because the moon is simply a sunlit subject at a known brightness. This calculator applies the Looney 11 rule with phase adjustments to give you the exact settings.
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How to use this moon exposure calculator
Pick the moon's phase and your ISO, and the calculator returns the shutter speed at your chosen aperture. The math: a full moon is a sunlit surface worth about EV 13.6 — the Looney 11 baseline (f/11 at 1/ISO). Each phase step dims the lit surface by roughly one stop. Meter with spot mode directly on the moon if your camera supports it; the Looney 11 numbers are the failsafe when the meter lies (it will, because the sky around the moon is black).
Worked example
A full moon at ISO 100, f/11: Looney 11 gives 1/100 s. Shoot the same moon at ISO 400 and you'd use 1/400 s (or f/22 at 1/100 s). A quarter moon is two stops dimmer: at ISO 100, f/8, that's about 1/50 s. Handheld is fine for the moon — at these shutter speeds camera shake is rarely the problem; a tripod matters when you zoom to 300 mm+ or shoot the moon with a landscape.
Moon exposure FAQ
What is the Looney 11 rule for moon photography?
Looney 11 (the moon's equivalent of sunny 16): full moon at f/11, shutter 1/ISO. At ISO 100 that's 1/100 s at f/11 — the moon is a sunlit subject, so it needs a daylight exposure, not a night exposure.
How do I expose the moon at different phases?
Start from full moon (f/11 at 1/ISO). Add one stop for gibbous, two for quarter, three to four for a crescent — the lit fraction of the face gets dimmer as it narrows.
Why is my moon overexposed when I shoot at night?
Your camera meters the dark sky and stretches the exposure — but the moon itself is sunlit and bright. Meter directly off the moon (spot mode) or use the Looney 11 settings and let the sky go black.
Can I photograph the moon and landscape in one shot?
The moon is about 12 stops brighter than a blue-hour landscape, so one exposure can't hold both. Shoot two frames and blend, or catch a crescent moon in twilight, which is much closer in brightness.