Did you just read an article, telling you to rush out and photograph the moon because it’s the latest rare moon event? Snow Moon, Blue Moon, Harvest Moon…. The labels seem to never end. And of course they all mention that the moon is so much larger than ever and will not be this large again this century.
Although the claims are not entirely false, this is just another piece of click bait to grab your attention. Rest assured that if the clouds obscure your view for the evening, you haven’t really missed anything, and if you think you did, you will get the same chance again by the next season change. The loss of opportunity gets even less important if you read on.
Because the moon orbits the earth in a not-so-circular path, it comes close to (perigee) and farther away from (apogee) us on a pretty regular basis. Even so, this difference in distance only amounts to about a 7% change in apparent size from the average moon, hardly measurable to the unaided eye despite the graphics that go along with said articles. The Supermoon is simply a full moon that arrives within ten days of apogee and this happens three or four times every year. While the moon sometimes looks much larger down by the horizon, or when framed by nearby objects, the actual size really doesn’t change. Don’t believe me? Shoot it one evening when it rises and then again when it is nearly overhead and the difference, if any, will be hard to discern.
Many of the photos you see depicting the supermoon as anything other than the plain ol’ moon is purely a matter of perspective or something done up to alter reality. Consider this image of the January 2019 Super Blood Moon which was a total eclipse for much of the northern hemisphere. This is a composite of a sequence of images taken at 1000mm combined with a scenic taken a month earlier at 15mm. Pretty? Sure. Accurate? Not at all.
And here’s another one with the same sequence but a different background image.
So, now that we have the size issue out of the way, how do you shoot decent pictures of the moon? Well, one of the basic rules of photography is the Sunny 16 Rule that states that for a sunny scene, you set your aperture to f16 and choose a shutter speed close to that of your ISO, and you will end up with a pretty decent exposure. If you are familiar with the exposure triangle, you can change any one of these parameters and calculate how it affects the others. And with the digital cameras of today that allow you to look at your histograms, you can simply fine tune your exposure from there. Unless you are spot metering, auto exposure will likely fail miserably, heavily overexposing the moon because of the expanse of dark sky. You just need to make sure that your shutter speed is high enough to overcome camera shake as well as the relative motion of the moon across the sky and that will depend on your focal length, the stability of your tripod, etc. Again, with digital photography, it is easy to experiment.
This begs the question of why the Sunny 16 Rule works for the moon AND the earth. It’s simply because it’s based on incident illumination. Both the earth and the moon are roughly the same distance from the sun (93,000,000 miles, plus or minus 25,000 miles or so) so they essentially receive the same illumination. It just looks so bright because of it’s placement in a dark sky.
So, the next time you read about an upcoming moon event, or your friends ask if you are going to shoot the upcoming “worm” moon, unless it’s an eclipse, don’t worry about rushing out to grab pictures. Instead, just pick a time at your convenience, when the weather cooperates with your schedule. And it doesn’t have to be during a full moon either. Often, the partial phases of the moon make for a better composition plus they reveal even more crater detail.
Experiment with shooting the moon in a composition as well as with building a composite with new or existing scenes. And once you master the moon, consider moving on to the sun. Yes. With special safety considerations, the sun can also be very fascinating to view and photograph.