8 low light focus tips
The world looks a little different and a whole lot more interesting through the lens when the light is low. So low light shooting can be very rewarding, but of course comes with it’s own set of challenges. The first one being how can your camera see to be able to focus in low light?
More specifically, when you’re shooting in low light it is often for the very characteristics that low light offers, so you don’t want to blast the scene with flash. So how do you shoot in really low light when you don’t have a flash?
I’ve listed the processes that I would use in the order that I would use them, or at least think through before trying one. As you can see, I prefer to start with the simple low light focus solutions.
- Focus on a bright area
- Focus on your subject’s edge
- Use the AF illuminator
- Focus using live view
- Back button focus
- Light it up with a flashlight
- Focus manually
- Use hyperfocal focusing
1. Focus on a bright area
If there is a brighter patch in the scene on the same focal plane as the part you want in focus, aim your focus there, lock focus and then recompose before taking the shot.
2. Focus on your subject’s edge
If you can make out the edges of your subject, it means that part of the subject is brighter than another part. It helps your camera’s focusing system, which works by detecting contrast. Aim your focus point there, lock focus, recompose and take the shot.
That’s all fairly straight forward, but how do you lock focus?
How to lock focus
Before we move on to other methods of focusing in low light, here’s how I would go about “locking focus” in challenging conditions. Achieve focus, then switch from autofocus to manual focus and shoot away. This assumes that your subject is not moving.
If your subject is moving, the AF illuminator, if close enough, and live view are your friends.
3. Use the AF illuminator
When it is too dark for your camera to see properly it can’t focus and that’s when the AF-assist illuminator is useful if your subject is not too far in the distance. It is the light at the front of your camera that also doubles up as the self timer lamp and red-eye reduction lamp. It will shine enough light for the camera to see the subject and then be able to focus. You can set it using your camera menu.
To activate your AF illuminator, first make sure that your focus is set to single focus. For Nikon that is AF-S (single servo) and for Canon it is called One Shot AF. In this mode when you part depress the shutter button to focus, the camera will focus and hold that focus. If you keep holding the shutter button half way down and recompose your shot by moving your camera (while still on the same focal plan of course), the area you focused on will still be in focus.
Check where you have your focus point positioned. With some older cameras the focus point needed to be in the middle of the viewfinder. With newer models, this may not be necessary, but it does still need to be near the middle. It is not possible to use the AF illuminator when the focus point is towards the edge of your frame.
When is the AF illuminator useful for focusing in low light? Bride and groom’s first dance.
What if your subject is too far away for the AF illuminator to be effective?
4. Focus with live view
Your best option is to switch your camera to live view. Your camera’s autofocus works differently in live view. Without delving into the technical details of how focus works (phase detection autofocus vs contrast detection autofocus), live view uses contrast detection autofocus. So it is more accurate in low light conditions and works in all areas of the frame, even at the edges. The only requirement is that there is enough light for the sensor to analyse the image.
Bear in mind that when you are viewing your scene with live view, rather than through the viewfinder, your camera won’t be well supported as your arms will be outstretched. You might therefore get camera shake in your image, so a tripod is essential.
What would you shoot using live view for focusing in low light? Light trails from cars.
5. Back button focus
When you use back button focus with your focus set to single servo / one shot AF, your focus will hunt until it locks. In continuous focus it will hunt, lock on the subject and stay with it, even if it moves (as long as your focus point remains on your subject of course).
Once focus is locked, simply depress the shutter to take the shot. Without back button focus, you run the risk of your camera trying to refocus before you depress the shutter.
Further reading on back button focus – Why back button focus is your BFF, and how to use it
When are you most likely to use back button focus? With moving subjects.
6. Light it up with a flashlight
I love a low tech, old school fix to problems. Enter the flashlight – and who doesn’t love playing with a flashlight?
It’s always a good idea to put a flashlight in your bag before heading out on a shoot that might potentially be in low light conditions. Apart from ensuring that you don’t trip over stuff, it is a really useful focusing tool. There are two ways that you can use it:
- Aim it at your subject, autofocus, lock focus, switch off the flashlight and take the shot.
- Place the flashlight in the scene, autofocus, lock focus, remove the flashlight from the scene and take the shot.
See, low tech is always simple and very often the solution.
What would you shoot using a flashlight to focus in low light? Still life or landscapes with focus on a still foreground subject.
7. Focus manually
Speaking of low tech. There is always the option to manually focus your lens. I think because we get so used to autofocus, we don’t think about using manual focus nearly enough. Low light is the perfect time for it.
The first point to note before you do anything is turn off the autofocus to avoid damaging the autofocus mechanism by turning the focus ring.
Of course, as this is photography, there are options of how to go about focusing manually
- straight up manual focus
- zone focusing
The straight up one
There’s the method that is most obvious – set your camera and lens to manual focus, look at the subject through the viewfinder and turn the focus ring until the subject is perfectly sharp. Take the shot.
Zone focusing / scale focusing
When you use the lens scale to focus manually, you are zone focusing, also called scale focusing.
Before I start, please note that not every lens has a lens scale. Particularly cheaper lenses. But that doesn’t mean you can’t zone focus.
If you look at your lens you will see the infinity symbol (looks like a figure 8 on its side) on one end of the scale. The other end of the scale shows your lens’ minimum focusing distance. The distances are written in both feet and meters. As you turn the focusing ring you will see that the numbers move around. The number resting in front of the alignment point is the distance at which you will achieve sharp focus.
As using the lens scale method to focus in low light relies on your judgement of distance, use a wide angle if possible and a narrow aperture to give yourself some wiggle room – in other words, greater depth of field.
To fully understand how to use the lens scale, you must first become familiar with how depth of field works.
Briefly, this is that depth of field extends behind your subject by 2/3 of the depth of field, or zone of focus, and also in front of your subject by 1/3 of the depth of field, or zone of focus. There are 4 variables that affect depth of field – aperture, focal length, distance and camera sensor.
Further reading on depth of field – Using depth of field for gorgeous photography composition
There are some great depth of field apps for your phone – I’ve got F-Stop Calculator on my iPhone. Also, here is a link to a really handy depth of field calculator: https://www.photopills.com/calculators/dof
Just having a play around with these calculators should help you to understand the variables of depth of field.
When are you most likely to use scale focusing / zone focusing in low light? Street photography.
8. Use hyperfocal focusing
I’ve listed hyperfocal focusing last, purely because it is what I would use least as I do more portraiture than landscapes. Hyperfocal focusing is mainly for landscapes, or images taken from a distance.
The apps and website link above also have hyperfocal calculators to help you decide on your camera settings.
If something is far away from you, set your focus to manual, turn the focus ring to infinity and ensure that your aperture is set to the smallest setting possible. The acceptably sharp area of the image will be everything from half the hyperfocal distance through to infinity.
When are you most likely to use hyperfocal focusing? Landscape photography requiring front to back sharpness.
If you have any questions about how to focus in low light, let us know in the comments.
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