Gear Doesn’t Matter—Except When it Does
Regular readers know that I’m not much of an equipment geek. It’s not that I don’t think equipment is important—a photographer needs good tools. It’s just that I think light, composition, technique, vision, and imagination are more important. In other words, how you use the tools is more important than what tools you use.
But sometimes the right gear can make a difference. Two weeks ago I was recording video segments for some online courses I’m working on (more about that later!), and needed a digital SLR that could record video—something my trusty old Canon 1Ds Mark II can’t do—for some “through-the-lens” views. So I called up my friend Jim Goldstein. Many of you know Jim through his popular blog and social media streams. Jim also works for Borrowlenses.com, and he set me up with a Canon 5D Mark III for my video shoot, and then asked, “Is there anything else you need?” Hmm… well I’ve been wanting to test the Canon 24mm f/1.4L lens for night photos, so yes, there was something else!
I needed the equipment in a hurry, but luckily the Borrowlenses online ordering system was easy to use, and with overnight shipping I had the camera and lens the next day. The rental period coincided with a new moon—the perfect time to photograph a star-filled sky and the Milky Way.
Night photography has been a specialty of mine for a long time. Since the early 1990s I’ve been photographing moonlit landscapes, star trails, comets, and making wild, brightly-colored light-painted images.
But I’d never captured the Milky Way before. With film the only way to photograph the Milky Way is to use a star-tracking system, which moves the camera in sync with the stars and allows you to make long exposures without the stars becoming streaks. This won’t work if you want to include, say, a tree in the foreground, because the camera’s movement will blur the tree.
Today you can push up the ISO on most modern digital SLRs high enough to record vivid images of the Milky Way with relatively short exposures—short enough to prevent apparent movement in the stars—and keep the camera stationary so you can include foreground objects.
But my Canon 1Ds Mark II, while great for daytime landscapes, and for most nighttime situations, has a maximum ISO of only 3200. The 5D Mark III I rented can go up to an amazing 102,400 ISO, and the 24mm lens’s maximum aperture of 1.4 is a full three stops faster than any of the lenses I own.
After testing the new camera, shooting some video at Tenaya Lake, and having dinner at the fabulous Whoa Nellie Deli in Lee Vining, Claudia and I drove back after dark to Olmsted Point, the land of beautiful, twisted, photogenic junipers. I quickly discovered that it’s fairly easy to make images of the Milky Way with the right equipment.
Focusing in the Dark
However, while modern DSLRs make photographing the Milky Way relatively easy, there are some pitfalls you have to watch out for. One of the thorniest issues with night photography is focusing in the dark. In the old days you could just focus the lens at infinity and be done. But most modern lenses actually focus past infinity, so finding the right focus can be tricky, and missing the focus even slightly with a wide aperture can give you blurred, unusable images.
Usually I solve this problem by focusing manually on a bright, distant object like the moon, car lights, or even a bright star. I also have a powerful, hand-held spotlight that can illuminate a foreground tree or rock enough to focus on it.
But with the 5D Mark III I found a better way. Using Live View, with Exposure Simulation on, I could zoom in on the live view image and focus manually on an individual star, or a tree lit by just my headlamp. This was both easier and more accurate than any other night-focusing method I’ve used. Very cool!
I don’t know if this technique will work with other cameras. With most cameras, once the light level drops below a certain point live view is useless—all you see is a black screen. The live view mode on the 5D Mark III is amazingly sensitive, and though the image is very grainy you can focus accurately in almost complete darkness. I’d be curious to hear if other cameras are sensitive enough to focus in the dark with live view, so if you’ve tried this with your model please leave a comment and let me know whether it worked.
Depth of Field
Even with the considerable depth of field afforded by the wide 24mm lens I found that I couldn’t get both foreground trees and distant stars in focus at f/1.4, so I had to stop down to f/2.8 or f/4. Having that super-wide maximum aperture sounds great in theory, but in practice it only helps if everything in the scene is distant.
The reason you need wide apertures and high ISOs to capture the milky way is because stars move. If you keep the shutter open too long the stars become streaks rather than pinpoints of light.
How long an exposure does it take to turn the stars into streaks? That depends. The north star doesn’t move at all—you can keep the shutter open for hours and it will still look like a pinpoint. So stars in the northern sky, close to the north star, move relatively slowly, while stars in the southern sky move relatively quickly. If your camera is pointed north you can use longer exposures than if the camera is pointed south.
Also, telephoto lenses magnify the movement, and require shorter exposure times than wide-angle lenses. With longer lenses (say 90mm or more) you need to keep shutter speeds down to 5 seconds or less; with wide-angle lenses (say 24mm or shorter) you can get away with a 30-second exposure. Over 30 seconds the stars will streak a bit, but this won’t be too noticeable unless you look closely. Exposures of 15 seconds or less are better if you want the stars to really look like pinpoints.
So within those time constraints the brightness of the Milky Way depends on the ISO and aperture. The wider the aperture, the more light comes through the lens to hit the sensor, and the brighter the image. The higher the ISO, the more that light signal gets amplified, and the brighter the image.
Since I needed apertures of f/2.8 or f/4 to get enough depth of field for most of these images, and the shutter speed couldn’t be more than 30 seconds (with a wide-angle lens), the shutter speed and aperture were predetermined. The only way to vary the exposure, and increase it enough to show lots of stars, was to push up the ISO. I found that an ISO of 6400 or 12,800 was enough to show the Milky Way. The 5D Mark III performed well at those high ISOs. There’s noise, to be sure, but it’s quite acceptable, and becomes even less apparent with a little noise reduction in Lightroom.
A (Relatively) Simple Procedure
Once you’ve figured out the parameters, the actual procedure for capturing a photograph of the Milky Way is pretty simple. First, focus. Then stop down the aperture to get enough depth of field (choosing the aperture is a matter of trial and error, or experience.) Push up the ISO, and then open the shutter for 30 seconds (assuming you’re using a wide-angle lens). Try different ISOs to see their effect on the exposure and Milky Way. You can also try to shorten the exposure to 15 seconds to get more truly pinpoint starts, but you’ll have to push the ISO up even higher.
Light painting a foreground object makes things more complicated. That part—the light painting—is more art than science, and this post is already too long, so maybe I’ll write about that another time!
For the image at the top of this post I actually used my 17-40mm f/4 lens at 19mm, because I needed something a little wider than 24mm to get the composition I wanted. I stopped this lens down to f/5.6 because I knew it wouldn’t be sharp enough at f/4, but even at f/5.6 and 30 seconds the Milky Way showed up well at 12,800 ISO.
I’m happy with the images I made, but more importantly I had a great time up at Olmsted Point. The night was warm, the stars were bright, and it was exciting seeing the Milky Way pop up brilliantly on the back of the camera after a 30 second exposure. And, I have to admit, it’s fun to play with new equipment from time to time. (Caution: renting gear may become habit forming.)
Michael Frye is a professional photographer specializing in landscapes and nature. He is the author and photographer of The Photographer’s Guide to Yosemite, Yosemite Meditations, and Digital Landscape Photography: In the Footsteps of Ansel Adams and the Great Masters, plus the eBooks Light & Land: Landscapes in the Digital Darkroom, and Exposure for Outdoor Photography. He has written numerous magazine articles on the art and technique of photography, and his images have been published in over thirty countries around the world. Michael has lived either in or near Yosemite National Park since 1983, currently residing just outside the park in Mariposa, California.