How To Focus In The Dark

So you're at a night shoot, the aircraft looks fantastic under the floodlights, and your autofocus won't lock on. The lens hunts back and forth, you try again, and when you finally get home half the shots are soft.

It happens to us all! It's a common problem after dark, and with the night shoot season under way it's a good week to get on top of it. Let's look at why autofocus struggles at night and what to do about it…

1. Why autofocus hunts at night

Autofocus works by finding contrast, the edge where something light meets something dark. In daylight an aircraft is full of edges. At night, a grey airframe against a black sky with one floodlight on it has very few, and the camera can't find anything to lock on to. Most cameras are also far better at focusing in low light with their centre point than with the points near the edge.

2. Put the focus point on a lit edge

Switch to a single focus point and put it on the brightest, sharpest edge you can find: the line where a floodlit panel meets shadow, a white stencil, the edge of the canopy rail or a lit propeller tip. Avoid plain dark panels and the sky. If you use the centre point and then move the camera to compose, keep the aircraft roughly the same distance away so focus stays in the right place.

3. Focus once, then leave it

For a static aircraft, there's no reason to refocus for every shot. If you use back-button focus, focus once with the AF-ON button and then just press the shutter. If you don't, focus as normal and then flick the switch on the lens from AF to MF. The focus stays exactly where it is until you touch the ring.

4. When autofocus won't lock, go manual

Switch the lens to manual, turn on live view or use the viewfinder on a mirrorless camera, and magnify the view as far as it'll go on a lit detail. Turn the focus ring slowly until the detail is as sharp as you can get it (some bodies use a focus-peaking function), go just past it, then come back. It might be slower than autofocus, but it works!

5. Don't trust the infinity mark

If you're focusing on something a long way away, like an aircraft across the airfield or the moon, the infinity mark on the lens isn't accurate on most modern lenses. Most will focus past infinity, so turning the ring all the way to the end gives you a soft shot. Focus on a distant lit detail and magnify it to check instead.

6. Turn off the AF assist light

The little orange or red light on the front of many cameras helps them focus in the dark, but at a night shoot it shines straight into everyone else's shot. Turn it off in the menu before you arrive. If your camera has a low light AF mode, use that instead, as it gives the camera more time to find focus without lighting anything up.

7. Check it as the night goes on

Zoom in to 100% on the first shot of every new set-up to check focus, not just the exposure. On a cold night, or after you've zoomed in or out, focus can shift slightly, so check it again every so often.

Own The Night

If you've got night shoots coming up this winter, our Own The Night guide covers the whole process in 10 clear steps, including the focus method we use for consistent sharpness at night, how to compose and focus when your eyes are struggling, and the lens setting that softens night shots. It's a 30-page PDF with a quick reference checklist to keep in your bag, and it's just £7.

Get the guide here: www.coaponline.com/own-the-night

Inside COAP Online, the full version of this tutorial is in The Merge, with the camera settings to change and a step-by-step method for focusing manually in the dark.