Shooting in the dark can be challenging because of the difficulties in obtaining accurate focus. When the light is too dim, the lens will start to hunt. The auto focus sensor on your camera simply cannot see enough light to work in poorly lit situations. If you have experienced something like this, the following tips on how to focus while shooting in the dark may help.

Many cameras have AF-assist illuminator that can be used to illuminate the subject when the shutter is pressed half way down. You need to make sure it is enabled on the camera in the settings. Sometimes it may be enabled on the camera but other camera settings may override it. As I talked about in my previous post Old Camera, New Learning, the focus assist lamp does not turn on if the focus mode is in continuous auto-focus mode. After revisiting the user manual, the Nikon D200 actually requires a few conditions met before it will turn on. They are:

  • The camera must be in the S (single-servo autofocus) mode
  • An AF lens is attached
  • Center focus area or focus area group must be selected or closest subject priority in effect

On the Nikon D200, the AF-assist illuminator has a range about 0.5-3m or 1’8″-9’10” with most lenses. For large lenses, the light may be blocked by lens or lens hood. So the lower limit may be pushed up. For example, when AF-S VR ED 70-200mm f/2.8G is mounted, the AF assist won’t work at ranges under 1.5m or (4’11”).

There is also an AF-assist illuminator on Nikon Speedlight flashes. When mounted on the camera, the camera will use the AF-assist illuminator on the flash instead of the one on the camera. Nikon SB-800 has a wide-area AF-assist illuminator that can work from 1m to 10m (3.3 to 33ft) depending on the lens used. It is also possible to use the AF-assist illuminator on the flash but not use the flash to illuminate the subject by changing a setting on the flash.

Nikon SB800 AF Assist Illuminator

If you need to use the Flash off camera, you can use the SC-29 TTL Coiled Remote Cord. It has an AF-assist illuminator at the camera flash mount point that overrides the SB-800’s AF-assist illuminator.

The effective range of AF-assist illuminator can still be limiting especially for landscape photography in the dark. There are some addition tips that may help.

  • Focus on something else that is about the same distance. For example, instead of trying to focus on the middle of mountain, focus on the ridgeline where there is a better contrast between the mountain and night sky. Or instead of focusing on a feature-less wall, focus on a window with light.
  • Use a flash light. You can get a small LED flash light with high intensity (>150 lumen) for 20-30 dollars. You should be careful not to use it on people’s eyes. This can get you focus on something ~100 ft away. Alternatively, you may want to consider some like this one, which uses green laser and has a range up to 40m (131 ft).
  • Manual focus. If nothing else works, you have only one choice. Some lens have distance marker that can help. Many have only a rough scale. Stopping the lens down to a small aperture can increase the depth of field to compensate the lack of precious focus.

Do you have other tips on how to focus in the dark? Please share with us using the comment box below.

Posted in: Tips and Techniques on January 8th, 2012. Trackback URI
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