I recently shot the moon with a Sigma 150-600mm f/5.6-6.3 super-telephoto zoom lens. It may not resolve quite as well as a telescope, but I was surprised and impressed by how sharp and detailed the moon appeared in my photos. Here’s how to shoot the moon with a super-telephoto lens.
First, you need to steady the camera. With a lens that long, you’re not going to want to handhold it. And since the moon isn’t exactly moving quickly across the sky, you can afford to stabilize it and have it locked down on a tripod. That’s the best way to do this, as it’s by far the most stable and will result in the sharpest shot. But you can get away with using a monopod or even resting the lens on a stable object such as a wall or a tree branch or the roof of a car. The tripod, however, is definitely best.
When picking a spot to deploy that tripod, consider avoiding as much city light and as many obstacles (like trees) as possible. To the naked eye, or with a shorter lens, shooting through tree branches might look interesting. But with a super-telephoto lens, the tree you’re shooting through is likely to be so far out of focus as to present nothing recognizable to the scene—only vague dark blurs obscuring the lunar surface. So, generally speaking, a clear sky is ideal.
Next, you’ve got to set the correct exposure. The picture included here was a RAW file shot at 1/1000th at ƒ/11 at ISO 1600. How did I arrive at this? I started with the aperture at ƒ/11 because I wanted as sharp an aperture as possible. Given the f/5.6-6.3 maximum aperture, two stops from wide open would be ƒ/11—and two to three stops from wide open is typically the sharpest aperture on a lens. So, to avoid aberration, I picked that sharp aperture and started with ƒ/11. I also knew I wanted a fast shutter speed because the lens is so long and the moon is, technically, moving—albeit very slowly. So with a 600mm lens, a shutter speed of at least 1/600th is ideal for sharp photos. The next fastest aperture beyond that is, of course, 1/1000th. Lastly was the ISO. I simply used the necessary ISO to achieve the shutter speed and aperture combo I had already dialed in. A glance at the back of the camera and a little scrutiny of the histogram shows exactly where the correct exposure is; it’s easy to see, and the RAW file provides plenty of exposure latitude anyway.
Finally, it’s time to focus. Manual focus is definitely key to keep your autofocus from searching in the dark. You might think you can just spin your lens’ focus ring all the way to the far end and you’ll be focused at infinity, but in practice, it doesn’t work that way. Infinity is actually reached just shy of turning the focus collar all the way to the end; go too far and you’ll see through the viewfinder that the image is out of focus. I also did a bit of focus bracketing, slowly turning the focus ring ever so slightly forward and back while shooting multiple frames, figuring if my eyes had fooled me I’d surely be able to pick out the sharpest exposure once I got the images into the computer.
Speaking of in the computer, with the ideal image selected, I used Lightroom’s Clarity slider to enhance a bit of edge contrast, and then I dialed down the highlights and dialed up the shadow detail a bit in order to maximize the detail on the moon’s surface. As I mentioned, it doesn’t have the resolving power of an actual telescope, but I still made out details such as Copernicus crater, lunar mares and on the edge of the moon, where raking light from the sun enhanced details such as craters, peaks and valleys that are actually well defined, even when substituting this long lens for a telescope.
The last thing I did was crop to take the moon from a fairly small circle in the middle of the frame to a large, frame-filling object that makes for a bolder, much more dramatic composition. Even with a super-telephoto lens and a bright, clear night, the moon remains a bit mysterious.