A long exposure bulb timer lets you count down timed exposures precisely in bulb mode — the camera setting that holds the shutter open for as long as you choose. Use the simple countdown for pre-planned durations, or enter your base exposure and ND filter stops to calculate the compensated time automatically, then start the countdown.
Enter a duration and press Start.
Quick Presets
How to Use the Long Exposure Bulb Mode Timer
Bulb mode photography gives you creative control over exposures longer than 30 seconds — from creamy waterfalls to star trails and light paintings. This long exposure timer eliminates the need to count in your head or watch a watch while holding your shutter release.
Simple Timer Mode
If you already know your target exposure time, select Simple Timer, enter the minutes and seconds, and press Start. The large countdown display and progress bar make it easy to see how far along the exposure is. A beep sounds when the countdown reaches zero — close your shutter at that exact moment. Use the preset buttons for common durations like 30 seconds, 1 minute, or 10 minutes.
ND Filter Compensation Mode
If you are using an ND filter and need to calculate the exposure time first, switch to ND Filter Mode. Select your base shutter speed (the metered exposure without the filter) and your ND filter strength in stops. The tool immediately calculates the compensated time using the formula: time = base × 2^stops. For example, a 1s base exposure through a 10-stop ND1000 becomes 1024 seconds — about 17 minutes. Click Start to begin the countdown immediately.
Bulb Mode Setup Guide
Set your camera to B (Bulb) mode — usually the last position on the mode dial past 30s, or accessible by scrolling shutter speeds past 30s in Tv/S mode. Mount on a sturdy tripod, compose and focus before attaching any ND filter, then connect your cable release or wireless remote. Press and hold to open the shutter, or lock the cable release, then start this timer. Release at the beep.
Tips for Successful Bulb Mode Shots
Always use a remote shutter release — pressing the camera body directly introduces vibration that blurs long exposures. If you do not have a remote, set your camera's 2-second self-timer to fire into bulb mode (some cameras support this). For star trail photography, use the 500 rule to find the longest single-frame exposure without star trails, then stack many frames in software for a cleaner result than a single hours-long exposure.
Frequently Asked Questions
Is this long exposure timer free?
Yes, completely free with no signup required. The timer runs entirely in your browser — no data is sent to any server. You can even add it to your phone's home screen for quick access during shoots.
Is my data private when using this tool?
Absolutely. Everything runs locally in your browser using JavaScript. No timer settings or usage data is transmitted or stored anywhere.
What is bulb mode on a camera?
Bulb mode (B) keeps the camera shutter open for as long as you hold the shutter button — there is no preset limit. This is essential for exposures longer than 30 seconds, such as star trails, light paintings, and daytime long exposures with very strong ND filters.
How does ND filter compensation work?
Each stop of an ND filter doubles the required exposure time. The formula is: compensated_time = base_time × 2^stops. A 1/125s base exposure with a 10-stop ND filter gives 1/125 × 1024 ≈ 8.2 seconds. This calculator does the math and starts the countdown automatically.
What equipment do I need for bulb mode photography?
You need a sturdy tripod, a cable release or wireless remote shutter to avoid camera shake, and optionally an ND filter for daytime long exposures. Frame and focus before attaching your ND filter — dark glass makes composition nearly impossible once attached.
Can the timer alert me when exposure is complete?
Yes. The timer plays a beep sound (using the Web Audio API) at completion. Make sure your phone or laptop is not muted before starting a long exposure. The progress bar also fills visually so you can glance at it during the shot.
What ND filter do I need for a 30-second daytime exposure?
Typically a 10-stop ND filter (ND1000) is used for 30-second daytime long exposures. In very bright sun at 1/500s base, a 10-stop ND gives about 2 seconds. For 30 seconds, you would need a 14-stop (ND16000) or stack filters. Use the ND Filter Calculator to find the exact combination.