Focusing at Night

by Beth Ruggiero-York

One of the most common questions about night photography is “How do I focus at night?”, and rightfully so, especially if you are accustomed to relying on autofocus in daylight. The sharpness of an image is critical to its success, and that includes night images.

In this post, I will guide you through four different methods for night focusing and help you to decide which method is right for different situations. These methods apply to establishing “infinity focus” so that everything at infinity is sharp, or nearer focus.

If you are familiar with the markings on your camera lenses, then you know that there is an “infinity” mark (∞) on the focus ring. Don’t be tempted to simply line the focus ring up with the infinity mark and expect sharp focus. The focus ring “stop” for autofocus lenses extends slightly beyond the infinity mark to give a cushion to the autofocus motor. In this case, manual focusing will be necessary to achieve infinity focus. For many lenses that are manual focus only (e.g., Zeiss), however, the infinity mark (in this case, turning the focus ring to its stop) is infinity. You should test your manual focus lens in the field to make sure this is the case, but once you know, it will make night focus on infinity a simple process.

Note: Remember that infinity focus is needed for night scenes without a close foreground. If your subject is closer than infinity distance, then you need to focus on either the subject or the hyperfocal distance (explained below).

Method 1: The Moon or a Distant Light After Dark

For images requiring infinity focus, if the Moon or even a partial moon (quarter moon or larger) is visible, you can take advantage of autofocus. If the Moon is not visible or is only a sliver, look instead for a distant, bright light to serve the same purpose.

1. Autofocus on the Moon or light using the center focusing point in your viewfinder;
2. Switch camera/lens to Manual Focus;
3. Use a piece of gaffer tape to secure the focus ring.

Method 2: A Distant or Near Object Before Dark

This method applies to images requiring either infinity focus or closer focus. If you arrive at the site and set up your camera gear before dark (this is always recommended), establish your focus on an appropriate object. Use a distant object (e.g., mountains in the distance) for infinity focus, or a near object (e.g., a building or automobile that you will be light painting) for closer focus. If you want both a near object in focus as well as, for instance, the sky, you will need to do one of two things: 1) Use hyperfocal distance (explained below); or, 2) Take two images, one of the foreground and one of the background (e.g., sky, mountains, etc.) and merge them as a composite in post-processing.

1. Autofocus on the desired subject using the center focusing point in your viewfinder;
2. Switch camera/lens to Manual Focus;
3. Use a piece of gaffer tape to secure the focus ring.

Method 3: Live View

Focusing after dark without the aid of the Moon or a distant light as described in Method 1 is easiest and most effective with Live View.

For infinity focus:

1. Find a bright star or planet with your naked eye
2. Locate the star or planet in the center of the viewfinder
3. Turn on Manual Focus and Live View
4. Zoom to 10x magnification
5. Focus manually on the star or planet (when it is smallest and “crunchiest”)
6. Lock down focus ring with gaffer tape

For near focus:

1. Turn on Manual Focus and Live View
2. Locate and illuminate the near subject in Live View with a bright flashlight
3. Zoom to 10x magnification
4. Focus manually on the illuminated subject
5. Lock down focus ring with gaffer tape

Method 4: Hyperfocal Distance

Hyperfocal distance is defined as the “closest distance at which a lens can be focused while keeping objects at infinity acceptably sharp.” There are several phone apps that can be used to calculate hyperfocal distance. Before the days of electronic conveniences, photographers carried a chart with them to calculate it. Some examples of these apps are PhotoBuddy, DOF Master, iDoF Calc, etc.

1. Calculate the hyperfocal distance using an app;
2. Measure out the distance either by pacing it off or estimating visually;
3. Use autofocus or manual focus, as appropriate, to establish focus;
4. Switch to manual focus;
5. Lock down focus ring with gaffer tape.

If you are using Method 4, and it is dark, you will need a very bright flashlight to illuminate an object at the hyperfocal distance to aid the focusing process. Ideally, you will pace out the distance and place a flashlight at the location, return to your camera, focus, and then retrieve the flashlight. I have listed hyperfocal distance last of the four focus methods because it is the most cumbersome to use at night. Nevertheless, when all else fails, it is an option.

The last thing I would like to recommend is practice, practice, and practice more, and soon focusing at night will become second nature.