Long Exposure Photography: Settings, iPhone Method and Cleaning Up Noise

Long exposure photography uses a slow shutter speed, from about a second to many seconds, so moving subjects such as water, clouds and car lights blur into smooth streaks while still objects stay sharp; it needs a steady camera, and long exposures tend to add noise that you can clean up afterwards.

Quick Facts
Shutter speed	Roughly 1 second to 30 seconds or more
ISO	As low as your camera allows (often 100)
Support	Tripod, plus a timer or remote to avoid shake
Daylight	An ND (neutral density) filter to darken the scene
Noise cleanup	imgmend denoiser

Basic Settings

1. Put the camera on a tripod and use a 2-second timer or a remote so pressing the button does not shake it.
2. Use manual mode or shutter priority and set a slow shutter speed.
3. Set the lowest ISO to keep noise down and a mid-range aperture (around f/8 to f/11 is a common starting point) for sharp detail.
4. In bright light, add an ND filter so the long exposure does not overexpose the picture.
5. Take a test shot, check the preview and adjust the shutter time.

Long Exposure on an iPhone

1. Turn on Live Photo in the Camera app and keep the phone steady, ideally on a stand.
2. Take the photo of a scene with moving water, lights or traffic.
3. Open the photo in Photos, swipe up and choose the Long Exposure effect.

The effect blends the frames of the Live Photo into one smooth-looking picture. It works best when the phone does not move.

Why Long Exposures Add Noise

Long exposures give the sensor more time to build up unwanted signal, so the picture can show speckles or hot pixels, especially in dark areas and on warm sensors. Many cameras have a long exposure noise reduction setting that takes a second dark frame to subtract the noise, which roughly doubles the time each shot takes. Shooting at low ISO also helps. For the basics of grain, see what is image noise.

Clean Up Noise After the Shot

1. Open imgmend.com and upload the JPG or PNG.
2. Compare before and after with the slider, then download the cleaned image.

Free use is 3 images per day with no account, and free downloads carry a small watermark that Pro removes. imgmend works on JPG, PNG and WebP, not RAW files. For more on grain, see how to fix grainy photos.

Frequently Asked Questions

What is long exposure photography?

It is photography with a slow shutter speed so motion blurs into smooth streaks while still objects stay sharp.

How do I do long exposure on an iPhone?

Take a Live Photo with the phone held steady, then open it in Photos, swipe up and choose the Long Exposure effect.

Why is my long exposure photo noisy?

The sensor collects more unwanted signal during a long exposure. Use a low ISO, try long exposure noise reduction, and denoise the photo afterwards.

Do I need a tripod?

Yes for a real long exposure. Any camera movement blurs the whole picture.

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