Long Exposure Timer

What it does

A simple stopwatch/countdown for tracking exposures longer than your camera's shutter dial can time (most cameras cap out around 30 seconds before requiring Bulb mode and a manual timer). Runs entirely in your browser — keep this tab open and your screen awake during the exposure.

What you'll need

• Nothing required — tap a preset for a countdown, or “Start stopwatch” to count up freely for a custom duration.

Steps

1. Put your camera in Bulb mode and get ready to open the shutter.
2. Tap a preset (or start the stopwatch) at the same moment you open the shutter.
3. Close the shutter when the timer reaches your target — presets alert you at zero.

Reading the result

In countdown mode, the timer counts down to zero and flags completion. In stopwatch mode, it just counts up — read off the elapsed time when you close the shutter yourself.

Tips

• Most phones dim or lock the screen after a short idle period — check your device's display/auto-lock settings before a long exposure so the timer stays visible.
• For exposures beyond about 15-20 minutes, consider a dedicated intervalometer instead — extreme long exposures raise sensor noise/heat considerations this simple timer doesn't account for.

What is Bulb mode?

Bulb mode is a shutter setting on nearly every camera with a full manual mode that keeps the shutter open for as long as you hold — or, with a remote or intervalometer, lock — the shutter button, instead of using one of the camera's preset timed speeds. It's how you shoot exposures longer than the camera's built-in timed range, which typically tops out around 30 seconds.

Why photographers use it

Some of the most recognisable long-exposure looks — silky waterfalls at several seconds, star trails at many minutes, light trails from traffic, a genuinely long night cityscape exposure — need shutter times well beyond 30 seconds, which no camera's normal shutter dial reaches. Bulb mode plus an external timer is the only way to hit those durations precisely, since the camera itself has no way to count that long on its own.

Which way of timing a Bulb exposure should I use?

For occasional long exposures under about 15-20 minutes, a phone timer like this one is perfectly fine — just make sure the screen stays awake and you start/stop it at the right moments. For frequent long-exposure work, or shots where even a second of button-press delay or vibration matters (deep-sky astro, very long cityscapes), a dedicated wired or wireless intervalometer that locks the shutter electronically avoids the camera shake of holding the button by hand, and doesn't depend on your phone staying awake and connected. Many modern cameras also have a built-in Bulb timer in their own menu, which is the most convenient option if yours supports it.

Common mistakes

• Letting the phone screen dim or lock mid-exposure. most phones auto-lock after a short idle period. Check your device's display/auto-lock settings before starting a long countdown, or you'll lose visibility of the elapsed time partway through.
• Physically holding the shutter button down for the whole exposure. this introduces camera shake for the entire duration. Use a remote release, an intervalometer, or your camera's own electronic Bulb-lock feature instead of holding the button by hand.
• Ignoring sensor noise and heat on very long exposures. extreme long exposures — many minutes — increase sensor noise and heat-related artefacts. This timer only tracks elapsed time; it's on you to judge whether stacking several shorter exposures would serve the shot better than one very long one.
• Forgetting long-exposure noise reduction can double your wait. many cameras automatically take a second, equal-length "dark frame" exposure after a long Bulb shot to subtract noise. If you're planning around a fixed total time, budget for that extra wait, or turn the feature off if you'd rather handle noise reduction in software instead.
• Starting the timer late relative to actually opening the shutter. a manual phone timer only measures accurately if you tap start at the same instant you open the shutter. Even a second or two of lag adds up as real error if you're trying to match an exact exposure length across multiple attempts.

Example settings

FAQ

Why does my camera's shutter dial stop at 30 seconds?

Camera shutter mechanisms are built around a fixed range of timed speeds. Anything longer requires Bulb mode plus external timing — which is exactly what this tool is for.

Can I lock my phone screen and still use the timer?

No — this timer runs in the browser tab and needs the screen on and the tab active to keep displaying and alerting you. Check your phone's auto-lock settings before starting a long exposure.

Does the timer keep running if I switch to another app?

It depends on your browser and device — many mobile browsers pause or throttle background tabs to save battery, which can affect timing accuracy. Keep this tab in the foreground for anything precision-critical.

What's the difference between the countdown presets and the stopwatch?

Presets count down to zero for a known target duration and flag completion automatically. The stopwatch counts up freely, for durations you don't know in advance or that don't match a preset — you read off the elapsed time yourself.

Do I still need a remote shutter release if I'm using this timer?

Yes, for anything beyond a few seconds. This timer only tracks elapsed time — it doesn't trigger your camera. You still need Bulb mode plus a remote release, intervalometer, or your camera's own Bulb timer to actually hold the shutter open.