I love autofocus. It’s fast, easy, and probably even more accurate than I would be in the quick shooting conditions I often encounter. But as good as autofocus has become on modern cameras, it still won’t work at night. I shoot a lot of city skylines, stars, and the Milky Way under conditions that require manual focus. Fortunately, it isn’t that hard, and I’ll teach you three ways to take great images in the dark.
Method #1: Pre-focus
One way to avoid manually focusing in the dark is simply to focus your camera ahead of time, while you still have enough light to autofocus. This can be done with any camera and lens. This approach also has the benefit of making it very easy to compose. If I arrive before it’s too dark, I often use this approach.
While it sounds pretty straight-foward, there are a few things to consider. First, you’ll need to be shooting on a tripod obviously (which you’ll probably need anyway to expose a shot in the dark). Second, you need to make sure you get focus locked. Once you have focused the camera, make sure you’ve switched to autofocus in the camera or lens, or use “back button” focus so that the camera does not attempt to refocus later. If you’re shooting stars, you should also make a note of the distance marking on your lens while you are focused at infinity. That way, you have a way to recover if you accidentally bump the focus ring on the camera later. A better solution may be to simply use gaffers tape to make sure the focus ring does not rotate after you have established focus.
There are some downsides to this approach, though. You need to arrive early enough while there is still light. And you may have limited options to adjust your composition later. But the next two options can be used to focus later.
Method #2: Use an artificial light source
There are actually a couple options here. The first is to simply focus on an artificial light source. That’s likely only an option if you are shooting cityscapes, but it can be helpful. And the artificial light source needs to be the right distance. In the tutorial video above, some other photographers started light painting a distant lighthouse. The lighthouse was far enough away that I was essentially focusing at infinity and could use it to help shoot sharp stars.
The second option is to bring your own light. This won’t help you with stars, but it’s a great way to focus on the foreground, up to a certain point. Just point a bright light at your subject, and focus manually (you will likely have enough light to see critical focus on the LCD, but probably not enough for the camera to autofocus).
To do this more than a few feet away, you need a very bright light. You can use a bright flashlight, but I prefer to use a headlamp because it is super convenient for hiking safely at night. I use the Petzl Tikka RXP. Its compact and offers a very bright 215 lumens, which allows me to focus on objects nearly 50 feet away with an f/2.8 lens. That brightest setting is unfortunately only for 10 seconds during its “boost mode”, but it’s easy to click the button to keep activating the boost. The Tikka RXP also offers a red light to save your night vision and uses micro USB to recharge. Petzl now also offers the REACTIK+. I haven’t personally used it, but it sounds interesting with 300 lumens.
For either of these approaches with an artificial light, it really helps to use a wide aperture lens (f/1.4-f/2.8).
Method #3: Focus on the stars
This is obviously only useful for focusing on the stars or other objects at infinity, so I frequently combine this with the previous method to shoot both foreground and background. You’ll need a fast aperture lens (f/2.8 or faster) or you won’t have enough light to see anything on your camera’s LCD. Make sure you set your LCD to it’s brightest possible value (use your maximum aperture, and long shutter or whatever settings help boost the LCD visibility). You will see a lot of noise on the LCD. So much, that it can be very difficult to see stars. First, make sure you pre-focus your lens close to infinity (ideally, you should have recorded this for your lens, as noted in method #1 above). The reason is that the stars will blur completely into the background if you aren’t relatively close to being focused. In other words, you are using manual focus to perfect things from a good starting point. Next zoom in the display around the brightest star in your composition. Then just twist the focus ring back and forth to make your stars look as close to tiny white dots as possible on the display. Take an exposure and zoom in the playback to confirm that you have a sharp image, and refocus if needed.