The aurora is one of the few subjects where the obvious advice, expose for longer, actively makes the photo worse. Longer exposures pull in more light, which in a dark sky sounds like exactly what you want. But the northern lights move while you are recording them, and everything that moves during an exposure gets smeared into everything else.
The result is a photo that is bright, green, and completely flat. The structure that made the display worth photographing, the vertical rays, the folds, the sharp edge along the bottom of a curtain, blends into one soft glow. This guide is about the balance point: long enough to record a faint sky, short enough to keep the shape.
Why the Aurora Fights Long Exposure
Compare it to two other night subjects. Stars move slowly and predictably, so very long exposures turn them into clean arcs. Meteors are so fast a long exposure catches the whole event at once. The aurora sits awkwardly between those cases.
A quiet aurora drifts slowly enough that a fairly long exposure holds its shape. An active display can restructure itself while the shutter is open, and then the curtains you saw never make it into the file. The faster the display moves, the shorter your exposures need to be, which is frustrating because fast displays are the most spectacular ones.
So there is no fixed number that works every night. What you need is the ability to change exposure length as the display changes, and that is exactly what the stock Camera app withholds. Night mode will take an aurora photo, but it decides the timing itself; there is no shutter speed control anywhere in the stock Camera app, on any iPhone model. Our guide to shutter speed control on iPhone covers why Apple leaves it out.
When and Where to Go
In the northern hemisphere, aurora season runs roughly from September through March. That window is about darkness rather than the aurora itself: at high latitudes the summer sky never gets properly dark, so there is nothing to see.
Beyond the season, three things decide whether you get a photo:
- Latitude. The further north, the more often the aurora is overhead rather than a smudge on the horizon.
- Darkness. City glow flattens the display and a bright moon washes out the fainter structure.
- Clear sky. Cloud beats everything else. A strong display behind overcast is invisible.
Dress for standing still. This is mostly waiting, and waiting is colder than walking.
Settings for Aurora on iPhone
Setting up in a long exposure app like Lento:
- Start moderate, then adjust. Duration runs from 1 second up to unlimited, plus a Bulb mode. Begin in the short-to-middle part of that range and move whichever way the sky demands. Mushy curtains mean go shorter; a frame too dark to read means go longer or raise ISO.
- Watch the exposure build. Lento stacks frames in real time and shows the accumulating exposure live on screen, so you see the image filling in rather than judging a finished file afterwards. On a changing display that is the fastest feedback you get.
- Set ISO deliberately. The manual range is 100 to 3200. Raising ISO lets you shorten the exposure, which protects the structure, at the cost of noise. Usually worth it on an active display, not on a slow one.
- Focus manually. Autofocus has nothing to lock onto in an empty dark sky. Set focus on a bright star, then do not touch it for the rest of the session.
- Use the timer. The 3 or 10 second timer stops your finger shaking the phone as the exposure starts.
Blend Mode Matters Here
Blend mode is the choice most people get wrong on aurora. Smooth mode uses mean blending, which averages frames together; that is what makes water silky and clouds soft, and it is also what erases the fine folds in a moving curtain. Light Trail mode uses lighten blending, keeping the brightest pixel from each frame, so bright rays stay defined.
Neither is universally right. On a slow, glowing arc, averaging gives a clean, low-noise frame. On an active display with sharp rays, lighten blending holds edges that averaging would soften. If unsure, shoot one of each.
Composition, Stability, and Files
Put something in the foreground. A pure sky frame of green light has no scale and no sense of place; a cabin, a tree line, or a ridge turns a light show into a photograph. Water is especially good because it doubles the display in reflection.
Support the phone on something rigid. Frame-stacking helps more than people assume: because Lento captures a continuous 30fps stream and combines frames on the GPU, each frame is exposed normally, so a handheld shot degrades gracefully instead of falling apart. A tripod still gives the sharpest stars. Keep a power bank in an inside pocket.
Shoot RAW if you plan to edit, and you almost certainly will, because the balance between sky and land is rarely right out of the camera. Lento exports 16-bit DNG at 8MP (3264x2448) with P3 wide color and full EXIF, leaving room to lift the foreground without wrecking the color in the sky. If the aurora never shows, our guide to night photography with long exposure on iPhone covers what else is worth shooting while you wait.
Frequently Asked Questions
Can the iPhone Camera app photograph the northern lights?
It can produce a recognizable image through Night mode. What it cannot do is let you choose the exposure length, because there is no shutter speed control in the stock Camera app. On an active display, where you need shorter exposures to keep the curtain structure, that is the difference between a photo and a green blur. Our long exposure guide explains the workarounds.
Why do my aurora photos look like a flat green haze?
Almost always because the exposure was too long for how fast the display was moving, so everything that shifted got averaged together. Shorten the exposure, raise ISO to compensate, and try a lighten-style blend mode, which keeps the brightest parts of each frame instead of smoothing them.
Can I shoot the aurora with the free version of Lento?
Yes, within limits. The free version of Lento includes Smooth and Light Trail modes with exposures up to 5 seconds, one export, and a watermark, which is workable for a bright display. Pro removes the time limit and adds RAW DNG export, at $9.99 per year with a 7-day free trial or $29.99 once for lifetime access. You will need an iPhone XR or newer running iOS 18.