Whenever I post long exposure film photography images, I receive a lot of questions in the comments regarding the settings I’ve used and the exposure times.
And while long exposure photography of any kind uses some of the same techniques across the board, there are some factors that are unique to certain subjects of long exposure photography but not others, such as photographing moon trails.
In this article, I wanted to address some of the specific challenges and aspects of making long exposure images of the moon as it traces its path across the sky, otherwise known as moon trails.
After a few years of trial and error with this subject, I recently made a moon trail image I was particularly pleased with, so I thought it might be helpful to go through some of the images I’ve taken over the years (both successful and not) so that you might be able to bypass some of the mistakes I’ve made in the past.
Challenges of Photographing Moon Trails
The most obvious challenge to shooting long exposures of the moon is planning out compositions given the moons ever changing phases and position in the sky.
Sometimes, it will just work out that you are out with your camera at night and the moon is in the right place at the right time for the shot you’re after. But the chances of this are unlikely, so some planning is probably going to be required.
Tracking the Moon Across the Sky
Like most people, I haven’t memorized the lunar calendar, or the track it takes in the sky, so I’ve found some smartphone apps that are useful in this regard.
There are free versions of moon tracker apps, such as Lumos: Sun and Moon Tracker, that use your phone’s GPS to give you a live view of where the moon is currently, what phase it is in, and also the path it will take across the sky at what time.
I chose to pay a small amount for one called Sun Surveyor that has a few other features, but the free app gets the job done, too.
Being able to see the path of the moon on your phone screen in real time can be really helpful when trying to visualize compositions.
My First Moon Trail Attempt
My first attempt at capturing a long moon trail image on film was not a success.
It was three years ago, and I just happened to be on a beach on Lake Ontario at night with my camera when I glimpsed the full moon coming over the horizon.
As it wasn’t planned, I tried to make calculations on the fly. The moon was full, so I anticipated it being quite bright, and decided to try using a 6 stop ND filter to compensate.
With my camera loaded with Ilford HP5 400 film, I used an f/5.6 aperture and composed my shot so the moon would rise over a grouping of rocks in the water.
This is the result of that 1 hour exposure. It is obviously terribly underexposed, but the moon was so bright it still picked up the trail.
I learned from that night that even under the brightest moon conditions, a 6 stop filter was far too much compensation.
Luckily, I didn’t come away that night empty handed, as I did take this 3 minute exposure with no filters before I took the one above.
The exposure time of a few minutes does not produce a long trail of the moon, but the movement of the moon is still visible.
Second Moon Trails Attempt
Two years later, I found myself planning another moon trail film shot near the same spot, but in the wintertime.
In hindsight, standing outside at night for an hour during a cold, Canadian winter was not the most pleasant decision, but I did manage to get a better image than my first attempt.
I knew the moon was going to be full, and the light reflecting off the snow gave off plenty of light, so I decided to try a 3-stop ND filter instead of the 6 stop.
I used Kodak Tri-X 400 film, a f/16 aperture, and a 1 hour exposure of the moon rising over an ice flow on the lake.
The exposure of this shot was much better than my previous attempt, so if you are trying a moon trail image where the moon is very bright, I would recommend no more than a 3-stop filter.
The following summer, I was cottaging on Lake Winnipeg, and found myself again on the beach with my camera looking at the moon.
I had used my moon tracker app to see that the moon would be setting diagonally and to my right. The rocks in the water made for an interesting foreground subject as well.
The moon was only a crescent, so it wasn’t providing much light itself. However, it was still dusk, and the west facing sky was still quite bright.
I knew that a long exposure with no filter at this time would probably be over exposed, so I threw on a 3-stop ND filter to compensate. I set my lens to f/8 with Ilford HP5 400 film, and exposed the shot for 30 minutes.
Sometimes, it’s hard to judge a long exposure shot where the light is changing throughout the shot. In this case, the 3-stop filter helped to keep the shot from over exposing while it was still bright, but didn’t leave the shot underexposed either.
My most recent attempt at shooting a moon trail image on film is also I think my most successful.
I was staying at a cottage this summer, and, the first evening, I noticed the half moon was high in the sky and setting.
I decided to set up my camera so I could take a long exposure once it got dark. I used my smart phone app to figure out where approximately the moon would set on the horizon line, at what time, and composed the shot accordingly.
Since I was at a cottage, I was able to set the camera up, trigger the shutter and let it expose for three hours while I did other things.
Moon trail images taken with water in the foreground have the added effect of the light’s reflection on the water.