The photography workbench · 06

Less light.
A little more time.

Calculate a longer exposure from your metered shutter speed and ND filters, then use a countdown while you shoot.

Explore all 15 tools ↗

Let the scene settle.

Calculate · set your camera · start

Original shutter speed, in seconds

Meter without the filter. Enter a fraction or seconds, such as 1/125 or 0.5.

ND filter strength (stops)

Additional filter (stops)

Presets set the first filter. Stacked filters add their stop values.

Your filtered exposure—

Combined strength: —
Exposure multiplier: —

See the difference

From falling drops to flowing silk.

Same waterfall. More time for the water to move.

Without filter1/30 sWith ND filter34.1333 s

A woodland waterfall with textured falling water, mossy rocks and a turquoise pool

Tripod · same aperture & ISO

Drag to compare 50 / 50

Drag across the photo or use the slider. Arrow keys adjust the comparison.

A longer exposure blends the moving water while the rocks stay sharp.

Loading the waterfall preview…

AI-generated photograph with simulated water motion. Brightness is matched by extending the shutter time; real results depend on the water’s speed and your camera setup.

Exposure countdown

00:00:00

Set the camera to the calculated exposure, then start the timer.

Play a short sound when finished

This timer does not trigger the camera. It checks elapsed clock time after tab switching. Keep the tab open; screen locking or browser suspension can delay the completion alert. Supported timer range: 0.1 second–24 hours.

Count the stops. Multiply the time.

Each stop halves the light reaching the sensor, so it doubles the shutter time needed for the same exposure. New time = original time × 2^{total stops}. A 6-stop and a 3-stop filter combine to 9 stops, or 512 times the original exposure.

Keep aperture and ISO unchanged for this comparison. Filter labels and real light transmission can differ, so check a test image and your histogram. Film reciprocity failure and changing light are not included. Filter strength here means stops, not optical density; an optical density of 3.0 is approximately 10 stops.

See what the extra time does in the shutter-speed simulator.