How do I take photos in low light without a flash?

Where the light actually is, the order to give up settings in, and why a support beats every other solution.

Difficulty: intermediate
Time: 30 min
Read: 3 min

Short answer

Open the aperture as wide as it goes, drop the shutter speed only as far as you can hold steady, then raise the ISO to make up the rest. If you can brace the camera against something, you can use a much slower shutter and keep the ISO down.

Low light photography is a series of compromises made in a sensible order. The mistake is making them in the wrong order — usually by protecting the ISO and sacrificing sharpness, which is the one thing you cannot recover.

What you'll need

A lens with a wide maximum aperture, if you have one
A small tripod or beanbag (optional)

Step by step

Find the light before changing settings.Move the subject nearer a window, a lamp or a shop front. One step towards a light source often gains more than two stops of settings.
Open the aperture fully.The widest f-number the lens offers. This costs depth of field, so focus carefully — at f/1.8 the sharp zone is very shallow.
Set the slowest shutter speed you can actually hold.Start at one over the focal length and test honestly. Stabilisation and good technique may let you go slower; check the results at 100% rather than assuming.
Then raise the ISO.Whatever is needed. Noise is a texture that can be reduced afterwards and looks acceptable in a print; blur is a failure that cannot be undone.
Brace against something.A wall, a railing, a table, a door frame. Bracing is worth several stops and it costs nothing. A small tripod or beanbag is better still.
Use the self timer or a remote on a support.Pressing the shutter is enough to shake a camera at slow speeds. A two-second timer removes that entirely.
Shoot in raw.Raw files hold far more shadow detail and let you recover an underexposed image and reduce noise much more effectively than a JPEG will.
Expose for the highlights, not the shadows.Blown highlights cannot be recovered; shadows usually can. Slightly underexposing and lifting in editing often beats getting a bright image in camera.
Use single-point focus on a contrast edge.Autofocus needs contrast. Aim the point at an edge — the rim of a glass, a collar, a bright line — rather than at a flat dark area.
Turn off automatic flash.Direct on-camera flash flattens the subject and destroys the atmosphere that made the scene worth photographing. If you must add light, bounce it off a ceiling.
Accept some grain.Grain in a low-light photograph reads as texture and mood. A sharp grainy picture is a picture; a clean blurred one is not.

Tips

Give up depth of field first, then shutter speed to your honest limit, then ISO.
Bracing against a wall is worth several stops and costs nothing.
Shoot raw in low light. The recovery latitude is the whole point.

Common mistakes

Protecting the ISO and letting the shutter get too slow — Noise can be reduced in editing and looks like texture. Motion blur is irreversible, so trading sharpness for a lower ISO trades something recoverable for something that is not.
Using the built-in flash — A small flash directly above the lens gives hard, flat, front-on light and a black background, which removes exactly the quality that made the low-light scene attractive.

If it doesn't work

Photos blurred at night

Cause: Shutter too slow to hand hold — Fix: Raise ISO, open the aperture, and brace the camera against something solid.

Very noisy images

Cause: ISO pushed very high with underexposure — Fix: Add light, use a faster lens, or use a support so the shutter can be slower.

Autofocus will not lock

Cause: Not enough contrast — Fix: Aim at a defined edge or bright line, or focus manually with magnified live view.

Bright subject, black background

Cause: Flash used — Fix: Turn the flash off, raise ISO, and let the ambient light record the room.

Questions people ask

What is a fast lens?

One with a wide maximum aperture, such as f/1.8 or f/1.4. It lets in far more light than a typical kit zoom at f/5.6, which is often two to three stops — the difference between a usable photo and a blurred one.

Is it better to underexpose and brighten later?

Slightly, and only in raw. Highlights that are completely blown cannot be recovered, whereas shadows usually can, though pushing very dark raw files hard does introduce noise.