Settings
Pick the shutter speed your meter gives without a filter, then the ND filter(s) you'll screw on. Everything is computed in your browser — nothing is uploaded.
Exposure with ND
- Total light reduction
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- Total ND factor
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- Transmittance
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An ND (neutral density) filter calculator for photographers. First pick the metered shutter speed without a filter (1/8000 up to 30 s), then pick the ND filter you'll screw on, and it converts the exposure time by the filter's light-reduction stops. ND2 is 1 stop, ND8 is 3 stops, ND64 is 6 stops, ND1000 is about 10 stops, and so on — the total ND factor is 2 raised to the number of stops, so 1/125 s with an ND1000 becomes about 8 s, the kind of long-exposure time you need to plan a shot. To stack two ND filters, pick a second one and their stops are added together so the combined reduction is handled for you. The result shows the shutter speed with the ND, the total light reduction in stops, the total ND factor, and the transmittance (how much light gets through), and it flags when the result passes 30 s and Bulb (B) mode is needed. Use it to plan smooth waterfalls and rivers, streaking clouds or water, and daytime long exposures — all before you shoot. Every calculation runs in your browser; the values you enter are never sent to any server or API.
How to use
- Pick the shutter speed your meter gives without a filter (1/8000 up to 30 s).
- Pick the ND filter you'll use (e.g. ND8 / ND1000). To stack two, pick a second filter too.
- Read off the shutter speed with the ND, the total stops, the ND factor, and the transmittance (nothing is sent).
FAQ
Are the values I enter sent anywhere?
No. The shutter speed conversion all runs in your browser. The values you pick are never sent to any server or API — everything stays on your device.
How do ND stops relate to the ND factor?
The ND factor is 2 raised to the number of stops: ND2 is 1 stop (×2), ND4 is 2 stops (×4), ND8 is 3 stops (×8), and ND1000 is about 10 stops (×1024). The shutter speed gets longer by that same factor.
How does stacking two ND filters work?
You add the stops together. For example, an ND8 (3 stops) plus an ND64 (6 stops) gives 9 stops total, a factor of ×512. Pick a second filter here and the tool adds them and recomputes the exposure time.
Why does an ND1000 show as 10 stops?
Names like ND1000 or ND8000 are conventional rounded values; the true figure is a power of two (ND1024 = 10 stops, ND8192 = 13 stops). This tool computes in stops (powers of two), so the factor shows as ×1024 and so on.