Focusing a digital camera in low light can be challenging, even if a camera has an autofocus assist lamp. This is particularly true for compact cameras that do not have a fast lens.
The main culprit of misfocused images is usually caused by low contrast, even more than low light. That’s why sometimes even in bright light you may have difficulty focusing if a subject lacks contrast.
Look for contrast
When having difficulty focusing, lock focus and exposure on something in the scene that has contrast by pressing the shutter button halfway. The subject should be of equal distance and lighting as the main subject so when you recompose the focus and exposure remains correct.
You may need to move the camera around a few times before achieving focus lock. Once focus is confirmed, reframe the scene and fully press the shutter button. This technique works best when a camera is set to a single area focus mode.
Misfocused or blurred images?
Sometimes a photo that appears misfocused is actually blurred due to camera shake. How can you tell the difference?
For misfocus, there is usually some area in the photo that is in focus, usually not where you intended it. A blurred image is blurry throughout the entire image.
Shutter speed and lighting
In low light, the aperture opens wider to let more light onto the sensor. The larger the aperture (smaller f number, eg. f2.0), the faster the shutter speed. Few people can hold a camera steady when shutter speeds are below 1/60th of a second, especially if the camera doesn’t have Image Stabilization.
If you can’t manually adjust shutter speed, increase it by increasing light on the subject. Let more light into the room, turn on more lights or use the flash. Also shoot at a wide angle rather than zooming in. Larger apertures are found at the wider end of a zoom lens, not telephoto.
You can also increase camera sensitivity by using a higher ISO number. The downside is that higher ISO numbers can cause image noise, with a resulting loss of detail. Fortunately, noise can be reduced with noise reduction software.
Steady the camera
Use a tripod or other support to keep the camera from moving. If not possible, hold the camera as steady as you can.
If your camera has a viewfinder, use it rather than the LCD to frame shots. Pressing the camera against your face helps minimize movement. If your camera doesn’t have a viewfinder, hold it in such a way to keep it more steady when using the LCD.