How I shot this: Lunar eclipse, 28 Sep 2015

Published on DRAFT

 Lunar eclipse, 28 Sep 2015 |  Flickr

Lunar eclipse, 28 Sep 2015 | Flickr

Introduction

The Moon.

This frigid dust-covered celestial body has been a steady occurrence in Earth skies for some 4,5 billion years. I have often wondered what humans in prehistoric times would have thought seeing the Moon slowly sliding across the sky every night and changing shape as the days wore on. It must have been awesome. I find it fascinating that Earth has a satellite. It is difficult to imagine life here without the Moon. For instance, ocean tides, caused by the Moon's gravitational pull which makes the oceans bulge on the sides closest and furthest away from the Moon, have a massive influence on marine life on Earth. And this pull has an influence on Earth itself. The Moon's pull causes the Earth to bulge slightly, too, which in turn has an effect on Earth's rotation and over time causes loss of angular momentum. In other words, the Moon is slowing down the Earth's spin. Eventually, the two bodies will be tidally locked. Or rather that would happen were it not for the fact that by then both bodies will have been burnt up by the Sun having been converted to a red giant (as I described in this article). 

Lunar eclipses occur because the Moon passes through the Earth's umbra or shadow. As can be seen in the photo, the shadow gradually covers the Moon until it has all but disappeared and then the process is reversed as the Moon leaves the shadow. At the beginning of an eclipse, Earth's shadow darkens the Moon only slightly. When the shadow begins to overlap more, the Moon typically turns a dark red-brown color. The color can vary based on atmospheric conditions. What is interesting in this photo is that the Moon was considerably redder leaving the shadow than going into it. The Moon appears reddish because of Rayleigh scattering – the same effect that causes sunsets to appear reddish – and the refraction of that light by Earth's atmosphere into its shadow.

A few technicalities

I shot this photograph using my Hasselblad 203FE and the excellent and in my opinion underrated Carl Zeiss Planar 2.8/80 T* FE using Kodak Portra 400. Because I am sometimes a lazy photographer, I shot it from the guest room on the top floor of our then house in The Hague, Netherlands. The film was scanned wet mounted on my Nikon Coolscan 9000 as described in this article.

An 80mm lens on a largish medium format negative is inadequate if one wants to show lots of features on the Moon's surface; smaller negative/sensor formats will increase the Moon's relative size in the frame. But to show the phases of an eclipse in one multi-exposure shot 80mm is a good focal length in medium format. 

Lunar eclipse exposure is straight forward but it requires adjustment as the eclipse progresses which means that manual exposure, not auto exposure, is the way to go. This is particularly important in a multi-exposure photograph. The full Moon is very bright, being directly lit by the Sun. And being an "ordinary" sun-lit object normal exposure rules apply, such as Sunny 16 (that is, to set the shutter speed at 1/ISO used at f/16 or derivatives thereof). The surrounding sky will be dark but in most cases that is not a problem since only the Moon is the object to be photographed. As the eclipse progresses the Moon will dim very much, causing considerably longer exposures. When the Moon is lit only by Earth's reflected light – a phase which goes by the lovely name Earthshine – the Moon is all but invisible. 

I used data from this website to calculate the exposure for the various phases. To be sure one gets accurate exposures it is often recommended to bracket, that is to shoot several frames at stops over and under the meter reading, but on a multi-exposure such as this one that won't work of course. 

For this shot I chose a colour negative film because of the very wide dynamic range of the Moon during the phases. As can be seen, even though colour negative films deal well with a wide latitude, parts of some of the phases are over-exposed.   

Time between

Multi-exposure.

Post-processing, going for less yellow