A lunar eclipse occurs when the Earth passes directly between the Sun and the Moon, casting a shadow onto the lunar surface. This alignment temporarily obscures the Moon from direct sunlight, causing it to darken. Unlike a solar eclipse, a lunar eclipse is completely safe to observe and photograph without protective gear. The change in the Moon’s brightness and color during this hours-long event presents a unique challenge for photographers.
The Phases of Visibility
The photographic viability of a lunar eclipse depends entirely on which of the three types is occurring, as each presents a vastly different light level. The least dramatic is the penumbral eclipse, where the Moon passes only through the faint outer part of Earth’s shadow, known as the penumbra. This slight dimming is often so subtle that it is difficult for the naked eye or a camera to capture a noticeable change, making it the least rewarding type to photograph.
The event becomes visually apparent during a partial eclipse, which begins when the Moon enters the Earth’s darker inner shadow, the umbra. A distinct, curved, dark “bite” appears on the lunar surface, representing the Earth’s shadow. Because a portion of the Moon remains illuminated by full sunlight, photographers must use relatively faster shutter speeds to correctly expose the brighter crescent area.
The most sought-after phase is totality, where the entire Moon is immersed in the umbra, creating the “Blood Moon.” Even in complete shadow, the Moon is not entirely dark because sunlight is filtered and refracted through the Earth’s atmosphere. This scatters blue light, allowing red and orange hues to illuminate the Moon. This reduced light requires the longest exposures and is the prime window for capturing the deep red color, measured on the Danjon scale.
Essential Equipment and Setup
Successful lunar eclipse photography relies on having a stable platform and a camera capable of manual control. A modern digital single-lens reflex (DSLR) or mirrorless camera is ideal, as it allows for precise adjustments to exposure settings throughout the progression of the eclipse. The choice of lens is critical and depends on the desired final image composition.
To capture the Moon as a large, detailed orb, a telephoto lens of 300 millimeters or more is recommended. For photographers aiming to include a foreground subject or a wider perspective, a wide-angle lens is necessary. Regardless of the lens chosen, a sturdy tripod is non-negotiable to prevent movement during the longer exposures needed, especially during totality.
Any movement during the shutter opening will cause motion blur, making a remote shutter release or an intervalometer essential. Using a remote trigger minimizes camera shake caused by physically pressing the shutter button. Extra batteries and memory cards should be on hand, as the event lasts several hours and continuous shooting depletes resources quickly.
Capturing the Eclipse
The initial step in capturing a sharp lunar image is to switch the camera to manual focus and set the focus point to infinity. Relying on autofocus will almost certainly result in a blurry image, as the camera struggles to lock onto the distant subject. Setting the camera to its fully manual exposure mode is equally important to maintain consistent settings.
A reliable starting point for the bright, non-eclipsed full Moon is the “Looney 11” rule: set the aperture to f/11 and the shutter speed to the reciprocal of the ISO value. For example, ISO 100 means a shutter speed of 1/100th of a second. As the partial phase begins, the Moon’s brightness decreases, requiring the shutter speed to be slower, perhaps closer to 1/125th of a second at ISO 200 to 400.
The exposure challenge becomes most pronounced during totality when the Moon is at its dimmest. To capture the faint red light, the shutter speed must be lengthened, often ranging from one to four seconds, while the ISO may need to be increased to 800 or higher. Because the Moon’s apparent brightness during totality is highly variable due to atmospheric conditions, it is recommended to bracket exposures by taking multiple shots at slightly different settings. For close-up shots, keep the shutter speed under one second to prevent the Moon’s orbital motion from causing noticeable streaking or blurring.
Post-Capture Considerations
Immediately following any exposure, especially longer ones, review the image on the camera’s screen, zooming in to check for motion blur or focusing errors. The highest-quality results are achieved by shooting in RAW file format, which preserves the maximum amount of light and color data for later adjustments. Shooting in RAW is beneficial for bringing out the subtle red and orange hues of the Blood Moon.
In post-processing software, basic adjustments to contrast and sharpness refine image details and enhance the visibility of lunar features. Adjusting the color balance and saturation can deepen the red tones of totality, making the “Blood Moon” effect more pronounced. For those who captured images throughout the event, the final consideration is creating a composite image. This involves digitally stacking a sequence of photos taken at regular intervals to illustrate the Moon’s progression through the Earth’s shadow.