Focusing well in low-light conditions can be a pain. Autofocus relies on the camera finding areas with good contrast, but when it’s dull, overcast or actual darkness, these areas don’t exist. The lens will hunt to and fro,never finding a proper focus.
Manual focus can be just as frustrating, peering through the eyepiece and trying to see what’s out there when edges and surfaces have no distinct features.
You can sometimes use a torch / flashlight to illuminate the scene whilst you set the focus, but this is not always practical. The target may be too far away, the bright light could ruin your night-sight or scare away the animal you want to photograph. If you do use a torch,use one that allows you to adjust the focus of the beam, ideally with a red or green filter on the lens.
The easy solution is to use a low-cost laser pointer pen. These produce a tight beam that delivers a small, bright, crisp, circle of light to the target and, by small, I mean perhaps 1cm across at 100m.
Having checked that you wont shine the light into anyone’s eyes, (take into account any possible reflections too!) point the laser at the target and focus on the dot of light.
Always use the manual focus setting – because ‘autofocus’ will try to re-focus the camera as soon as you switch off the laser!
Red and green laser pens both work well, though I prefer to work with a green light for two reasons: Green is brighter and it does not look like a gun sight illuminating a target, so people are far less concerned by it!
You can prop the laser pen on a convenient surface, hold it in place with gum,or go a little upmarket and superglue one to a cheap spirit-level hotshoe attachment so it clips directly onto your camera.
Obviously, use some common-sense with this tip. If a laser beam is likely to cause any damage, alarm or concern, don’t do anything until you’ve checked / gained permission and warned anyone who might need a warning. I don’t want you coming back and complaining because you shone a red laser dot on a police officer who then shot you!