Every aurora photo you've admired online comes down to the same four decisions: aperture, shutter speed, ISO, and focus. Get those roughly right and a phone-era camera can produce something worth keeping. Get them wrong and even expensive gear turns the aurora into a blurry green smear or a barely visible haze. This is the reasoning behind each one.
Shoot in Manual Mode
Auto mode will almost always get aurora exposure wrong — the scene is dark with a bright, moving light source in it, which confuses a camera's metering system. Manual mode (usually marked "M" on the mode dial) is non-negotiable for aurora work. It feels like more to think about at first, but it's really just three numbers you're setting instead of letting the camera guess.
Aperture: Open It All the Way
Set your lens to its widest aperture — the smallest f-number it supports. If your lens says "f/2.8," shoot at f/2.8. Aurora photography is almost always light-starved, so there's rarely a reason to stop down. The one exception is if your specific lens is noticeably soft wide open — some budget lenses benefit from being one stop down (e.g. f/3.2 instead of f/2.8) for sharper corners, at the cost of needing slightly more ISO or a longer shutter to compensate.
Shutter Speed: The Real Balancing Act
This is where most of the decision-making happens, because it's pulling in two directions at once:
- Longer exposures gather more light, which helps with faint or diffuse aurora and lets you use a lower, cleaner ISO.
- Shorter exposures freeze the aurora's structure — the pillars, curtains, and rays — instead of blurring them into a flat green glow. Fast-moving substorms in particular turn to mush at anything longer than a few seconds.
- There's also a hard ceiling: leave the shutter open too long relative to your lens and sensor, and stars stop being points and start becoming short streaks, because the Earth is rotating the whole time your shutter is open.
Faint, slow-moving aurora: go longer (8–15 seconds) to pull in more light. Bright, fast-moving aurora: go shorter (1–4 seconds) to keep the shape sharp, and raise your ISO to compensate for the lost light. If you're not sure which you're looking at, take a test shot at 5 seconds and adjust from there.
The star-trail ceiling (NPF rule)
The maximum shutter speed before stars visibly streak depends on your lens's focal length, its aperture, and how many megapixels are packed onto your sensor. Wider lenses tolerate longer exposures; more megapixels lower the ceiling, because smaller pixels reveal motion sooner. Working this out by hand mid-shoot isn't practical, which is exactly what our exposure calculator does automatically from your camera's specs.
ISO: Fill In What's Left
Once aperture is wide open and shutter speed is set by how the aurora is behaving, ISO is what's left to get a usable exposure. Push it as high as you need to — a slightly noisy photo you can see is better than a clean black frame. Modern cameras handle high ISO far better than they did even five years ago; noise you'd have found unacceptable in 2015 is often a non-issue with today's sensors and modern noise-reduction software.
That said, "how much noise is too much" is genuinely personal — it depends on your camera, whether the photo is headed to social media or a large print, and your own tolerance. There's no universally correct max ISO, which is why the calculator asks what you're comfortable with rather than assuming a number.
A textbook-correct exposure often looks worse on bright, fast aurora than one that's a stop or two darker. Overexposing the green channel flattens the aurora's structure into a featureless glow — the pillars and curtains that make a photo interesting disappear first when you push the exposure too bright. When in doubt, underexpose slightly and recover shadow detail in post rather than blowing out the highlights.
Focusing in the Dark
Autofocus generally fails at night — there isn't enough contrast for the camera to lock onto. Switch to manual focus before you're relying on it in the field, not after. A few reliable approaches:
- Focus on a bright star or the moon using your camera's live view zoomed in, adjusting the focus ring until the point of light is as small and sharp as possible.
- Focus on a distant light — a porch light, streetlight, or headlamp held by someone far away — during blue hour before it gets fully dark, then don't touch the focus ring again.
- Use focus peaking if your camera has it — a live-view overlay that highlights in-focus edges, making manual focus much easier to judge in the dark.
- Tape the focus ring once you've nailed it, especially in cold weather — focus rings can drift on their own as the lens contracts.
Infinity focus is not always the same as the infinity mark etched on the lens barrel — many modern lenses focus slightly past that mark at true infinity, especially in cold temperatures where the lens elements contract. Always verify with live view rather than trusting the marking.
White Balance and RAW
Shoot RAW, not JPEG, if your camera supports it. RAW files store the full sensor data, which means white balance is a decision you can freely change after the fact with zero quality loss — there's no need to get it perfect in the field. Many aurora photographers start with a cooler white balance (toward the tungsten/incandescent end) because it deepens the sky's blue-black and makes the green and pink of the aurora pop by contrast, but this is a stylistic choice you can always revisit later, not something to worry about while you're standing in the cold.
Manual mode · widest aperture · manual focus verified on a star · RAW capture on · fully charged battery, spare in an inside pocket · then dial in shutter speed and ISO once you can see how the aurora is actually behaving.
This guide covers technique. For the numbers themselves, use the exposure calculator, which factors in the live Kp index, moon phase, and your specific camera and lens.