Long Exposure Calculatorv1.0.0

Calculate your adjusted shutter speed when using neutral density (ND) filters for long exposure photography. Enter your metered base exposure time and your ND filter strength, and read off the new shutter speed you need to achieve correct exposure with the filter attached. Whether you are smoothing water, streaking clouds, or eliminating moving people from a scene, knowing the precise exposure time prevents wasted shots and bracketing guesswork.

• Select your Shutter Speed Input Mode. Choose Common Shutter Speeds to pick from a standard list, or choose Custom Value to type any shutter speed. Custom values accept fractions like 1/125, decimals like 0.008, or whole numbers like 2.
• Choose your ND Filter from the preset list, enter a custom number of stops, or select Stack Multiple Filters to combine several ND filters. When stacking, check each filter you are using and the stops are added together automatically.
• Press Calculate or simply change any input. Results auto-update after a short delay.
• Read the Results section for your new exposure time displayed in both exact seconds and a human-readable hours, minutes, and seconds format.
• Open Settings to enable step-by-step formula derivation, change the time display format, or toggle the ND filter reference table.
• Refer to the ND Filter Reference Table for the adjusted exposure across every common ND filter strength based on your current base shutter speed, making it easy to compare filters at a glance.
• Press Reset to clear all settings and return the calculator to its default state.
• Apply the core formula directly: New Exposure equals Base Exposure multiplied by 2 raised to the power of ND stops. For example, a 1/8 second base exposure with a 6-stop ND64 filter yields 1/8 multiplied by 64, which equals 8 seconds.

Plan your exposure in advance to save time in the field and reduce trial-and-error shooting. Long exposure photography opens creative possibilities that are impossible to achieve with normal shutter speeds, and accurate ND filter compensation is essential whenever ambient light, motion, or filter stacking pushes shutter speeds past what a camera meter can read directly.

• Landscape Photography: Calculate multi-second exposures to smooth ocean waves, rivers, and waterfalls into silky textures. Apply a 10-stop ND1000 filter to transform a 1/125 second reading into an 8 second exposure for dramatic water effects.
• Cityscape and Architecture: Determine exposure times of 30 seconds or longer to remove pedestrians and vehicles from busy urban scenes. Stack a 6-stop and a 10-stop filter for 16 stops total to achieve several-minute exposures during daylight.
• Cloud Streaking: Plan 2 to 5 minute exposures that transform static clouds into dynamic streaks across the sky, adding motion and drama to otherwise still compositions.
• Fine Art Photography: Explore extreme long exposures of 10 minutes or more using 15 or 20 stop filters to create ethereal, minimalist images where all motion dissolves into soft gradients.
• Astrophotography Transitions: Compute twilight long exposures during blue hour by combining ND filters with longer base exposures to balance ambient and artificial light.
• Education and Learning: Study the step-by-step derivation to understand the mathematical relationship between stops, filter factors, and exposure times. Use the reference table for a complete overview when comparing filter strengths.
• Filter Purchase Planning: Compare values in the reference table to decide which ND filter strengths to buy for your typical shooting conditions and desired exposure ranges.