ND Filter Calculator — Shutter Speed & Long Exposure Planner
Calculate your new shutter speed when adding an ND filter, or find which ND filter you need to achieve a target long exposure. Covers ND2 through ND32000.
✓ Free · ✓ No upload · ✓ Works offline in your browser
Result
New Shutter Speed
12.5s
With ND100 (6.6 stops)
Base: 1/8
Filter factor: 100×
Stops reduced: 6.6
ND Filter Stops Reference
| Filter | Stops | Factor | Best Use |
|---|---|---|---|
| ND2 | 1 | 2× | Slight exposure reduction, bright portraits |
| ND4 | 2 | 4× | Waterfall blur in midday light |
| ND8 | 3 | 8× | Shooting wide open in daylight |
| ND64 | 6 | 64× | Smooth water at dusk/dawn |
| ND100 | 6.6 | 100× | Versatile daytime long exposure |
| ND1000 | 10 | 1000× | 30s exposures in daylight (most popular) |
| ND32000 | 15 | 32000× | Extreme long exposures, daytime 4+ minute shots |
Frequently Asked Questions
How does an ND filter affect exposure?
An ND (neutral density) filter reduces the amount of light entering the lens by a fixed number of stops. An ND2 filter blocks 1 stop (halves the light), so you need 2× the shutter speed. An ND1000 blocks ~10 stops, meaning a 1/100s base exposure becomes a 10-second long exposure.
How do I calculate shutter speed with an ND filter?
New shutter speed = base shutter speed × ND factor. For a 1/100s base exposure with an ND100 filter: 1/100 × 100 = 1 second. With ND1000: 1/100 × 1000 = 10 seconds. Enter your base shutter speed and filter above for instant results.
Which ND filter do I need for a 30-second exposure?
Divide target exposure by base exposure to find the needed factor. If your base exposure is 1/250s and you want 30s: 30 ÷ (1/250) = 7,500. The nearest ND filter is ND6400 (13 stops). Use the 'Find Filter for Target' mode above and it calculates this automatically.
What is the difference between ND stops and ND numbers?
The ND number (ND2, ND4, ND1000) is the filter factor — how many times it reduces light. Stops are on a log₂ scale: ND2 = 1 stop, ND4 = 2 stops, ND8 = 3 stops. Each stop doubles the exposure time. ND1000 = ~10 stops. Some brands label filters by stops (3-stop, 6-stop, 10-stop) — both notations are shown in this calculator.
What are ND filters used for in photography?
ND filters are used for: smooth water in waterfalls and seascapes (2–30 second exposures), silky cloud movement in cityscapes, shooting wide-open apertures in bright daylight without overexposing, and video at cinematic shutter speeds (1/50s) in bright conditions.
What is the most popular ND filter for landscape photography?
The 10-stop ND (ND1000 / Big Stopper) is the most popular for landscape photographers. It turns a correctly exposed base of 1/30s into a 30-second long exposure in full daylight — long enough to blur clouds and smooth water into silk. The 6-stop ND64 is useful for shorter exposures at dawn/dusk.