August Moonset

August Moonset
Pentax 645z with 300mm f/5.6 at ISO 800 


Moonset, on the day of a full moon each month, is something most people don't usually see. It takes place at dawn, which is when we're usually tucked into our beds. But photographers are made of sterner stuff, and so on the morning of a full moon in August, 2014 I was up before 5am and cruising the back country roads in Clearview – farmland in north central Ontario. I had checked the weather forecast the night before, and saw that there was a pretty good chance of clear skies, so I set my alarm for 4:30am. Groan.

Not having a definite location in mind was a disadvantage, but it does add to the thrill of the chase. 

On this particular morning I found myself driving down country roads looking for a foreground. The setting moon can be pretty, but pretty isn't enough. There needs to be context, and in this case it meant needing an interesting foreground.

It was still quite dark when I pulled over, having seen this stand of trees and having decided that it was now or never. I set up the tripod and put the 300mm lens on my Pentax 645z (about 240mm equivalent in full frame 35mm terms), the longest lens I have for this system.

The shot called for an exposure of 6 seconds at f/22, using ISO 800. I used f/22 to get as much depth of field as possible, and decided that 6 seconds was about as long as I could afford without the moon blurring due to its motion. The necessary ISO turned out to be 800, which is essentially noiseless on the 645z.

File as shot

Not having too high an ISO was important, because I knew that the foreground field with its white flowers would be extremely dark. In fact with my eyes alone I could hardly see that there was anything there at all. There was no sunlight yet, just a glow on the horizon, and the moon wasn't providing much light because it was sinking fast into the lower atmosphere where dust and such was turning it a pretty orange, but reducing its power to illuminate.

The raw file above was the one that I used. As can be seen, very little by way of post processing was needed. Just a bit of cropping and a bit of selective lightening.

The 100% crop above shows that this exposure was able to retain good shadow detail as well as in the moon itself.  I experimented with lightening the whole image even more, but then the "feel" of pre-dawn was lost.  Sometimes less is more. 


This image and its analysis may be discussed on the LuLa Forum