A 20-stop neutral density filter (ND1048576) cuts light by a factor of 1048576. It's typically used for extreme minutes-long exposures (and the sun only with a certified solar filter).
Find your exposure in the chart, or use the calculator with your metered shutter speed.
20-stop ND exposure chart
| Without filter | With 20-stop ND (ND1048576) |
|---|---|
| 1/8000 s | 2 min 11 s |
| 1/4000 s | 4 min 22 s |
| 1/2000 s | 8 min 44 s |
| 1/1000 s | 17 min 29 s |
| 1/500 s | 34 min 57 s |
| 1/250 s | 1.2 h |
| 1/125 s | 2.3 h |
| 1/60 s | 4.9 h |
| 1/30 s | 9.7 h |
| 1/15 s | 19.4 h |
| 1/8 s | 36.4 h |
| 1/4 s | 72.8 h |
| 1/2 s | 145.6 h |
| 1 s | 291.3 h |
| 2 s | 582.5 h |
| 4 s | 1165.1 h |
Filter factor 1048576×, optical density 6.0.
Other strengths
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