Night photography is full of challenges. One of the biggest for beginners and pros alike is the difficulty of achieving accurate focus in very dark scenes. However, autofocus systems are constantly improving and many of today’s modern DSLR cameras can focus in the darkness that would have short-circuited the autofocus systems of cameras made just a few years ago.
Yet, the downside of most autofocus lenses is that they do not have hard stops at the infinity focus point. This hard stop was a boon to night and day photographers familiar with the pleasures of old-school manual focus lenses.
So, what are some helpful ways to focus in the dark?
1. Use manual focus
The quick remedy for a confused autofocus focus is to switch to manual focus. On a DSLR, if you can see the image clearly in the viewfinder in the dark, you should be all set. For critically precise focus, you might have to use some other techniques that we will get into below. One more thing to mention, manual focus lenses for night photography are usually more pleasurable to focus than autofocus lenses—they have a better feel, and the precise focus ring movement will assist you in getting accurate focus.
2. Infinity focus
Depending on your subject, the scene before your camera may be well past the focus range of your lens and into the “infinity” distance. In that case, setting your lens to infinity will allow anything past a certain distance to be in focus in the shot. Of course, as mentioned earlier, not all lenses have hard stops at the infinity mark, so that can make finding the true infinity point problematic. Keep on reading.
3. Pre-focus during the day
One trick is to focus your camera at a distant (infinity) object during the day using your trusty autofocus. Then, switch the camera to manual focus and use a piece of gaffer tape to keep the focus on the lens from moving. This technique could also work for objects that are closer than the infinity distance, but only the most dedicated photographers focus on something close-up during the day and then wait for darkness without moving their rig! Obviously, a pre-focused infinity setup will give you more versatility on a night outing unless you are doing a very specific shot.
4. Hyperfocal focusing
Distance is defined as the distance when the lens is focused at infinity, where objects from half of this distance to infinity will be in focus for a particular lens. Alternatively, the hyperfocal distance may refer to the closest distance that a lens can be focused for a given aperture while objects at a distance (infinity) will remain sharp.
Many older lenses, and some newer lenses have hyperfocal markings on the lens barrel. Basically, this allows you to set your lens so that, at a given aperture, you can determine at what distance objects in the frame will be in focus. So, without even looking at the viewfinder, you can set your focus.
5. Live View + Zoom
Many modern DSLR cameras feature a live-view function where the mirror flips out of the way and the camera acts like a digital mirrorless or point-and-shoot camera—showing the image on the LCD screen. This technology has been a blessing for night photographers because they now may be able to zoom in on the image on the LCD screen and manually focus with precision.
Once common in videography, focus peaking is part of some live view systems, mirrorless cameras, and point-and-shoot cameras, as well. Basically, focus peaking shows you regions in the frame where the highest contrast exists by highlighting them in a bright color.
The real advantage of focus peaking is when you are using manual focus lenses. Instead of relying on your eyesight to determine when the scene is in focus, focus peaking lets you determine the plane and depth of focus very quickly.
6. Target the autofocus on the edge of the bright object
If there is a region of high contrast in the image, usually near a relatively bright object, you can aim the camera’s autofocus at that area, and then, by moving the camera or by changing the autofocus point, see if the autofocus will lock on that region. Be sure you have your camera set to single autofocus and not continuous focus. If the autofocus locks on that area, keep the shutter depressed half-way or use the autofocus lock button, recompose and take the shot you want.
7. Shoot the moon
Is the moon up? Guess what? The moon is likely past the infinity focus distance of your lens. Point your lens at the moon, autofocus, and lock in that focus. If there is no moon you may be able to do the same trick with a bright star or planet depending on how advanced and sensitive your camera’s autofocus sensors are.
If you are not photographing a very distant scene, you can do two tricks with a handy flashlight or headlamp. The first trick is to use the light to illuminate your scene to give the autofocus system enough light and contrast to operate. The second trick is to place your flashlight into the scene at the distance you are trying to achieve focus. Focus on the flashlight, lock in focus, and then remove it before taking the photo.
9. Laser pointer
Just like the first flashlight trick above, you can hit a target in your scene with a laser pointer and train your camera’s autofocus sensor on that spot. The laser has the advantage of being more concentrated and therefore possibly less obtrusive than a wide beam of a flashlight. It will also be brighter and may be able to help get accurate focus at a longer distance. Astronomical laser pointers are useful for this.
10. Test shot + preview
Of course, you should always scrutinize your images for accurate focus by viewing them on the LCD and zooming in to the maximum extent possible. If you are shooting high ISO test shots of the scene, use these throw-away images to verify accurate focus as well as exposure—especially if the “real” exposure is very long. There is nothing quite like reviewing a 15-minute exposure to find out that your focus is off. Check your focus with your 15-second high ISO test shot instead!
But to upgrade the beauty of your night photographs, learn post processing techniques from Taming Light Photography. Online courses and Youtube tutorials are available to guide aspiring astrophotographers in their night photography post-processing. Check them today!