ND1000: ten stops
The ND1000 is the best known neutral density filter there is, and its name is wrong. Ten stops mean a factor of 210 = 1024. Manufacturers round it to "ND1000" on the box; the arithmetic uses 1024. That turns 1/125 s into 8.192 seconds. In the calculator below it is therefore called ND1024.
- Stops10
- Filter factor1024×
- 1/125 s becomes8.192 s
What this strength is good for
- Glassy sea: From about eight seconds onwards the wave texture disappears and the surface becomes a plane. This is the effect people buy this filter for.
- Drifting clouds: At 15 to 30 seconds clouds draw visible trails. A still sky gives you nothing even after a minute. This filter needs wind, or the long exposure is wasted time.
- Making people disappear: Anyone moving across a busy square is gone at 20 seconds. Anyone standing still is not, which is why architectural shots often take several attempts.
Calculating with ND1000
Pick a shutter speed. The fields are preset to ND1000.
hours : minutes : seconds : milliseconds
Exposure times with ND1000
On the left the speed your camera suggests without a filter, on the right what it becomes.
| No filter | With ND1000 |
|---|---|
| 1/500 | 2.0 s |
| 1/250 | 4.1 s |
| 1/125 | 8.2 s |
| 1/60 | 17.1 s |
| 1/30 | 34.1 s |
| 1/15 | 1 min 8 s |
| 1/8 | 2 min 8 s |
| 1/4 | 4 min 16 s |
| 1/2 | 8 min 32 s |
| 1 s | 17 min 4 s |
What to watch for
- Set focus and framing first: Through ten stops the viewfinder shows almost nothing and autofocus gives up. Focus, switch to manual, frame the shot, and only then fit the filter.
- Cover the viewfinder: On a DSLR, light enters through the eyepiece and lands on the sensor as a bright band. Many cameras come with a small cover on the strap for exactly this. Mirrorless cameras are not affected.
- A colour cast is the rule here: No filter gets past ten stops without a tint. Cheaper ones pull clearly towards magenta or blue. Shoot raw and fix the white balance, then it stays correctable.
- Past 30 seconds it is bulb mode: Most cameras stop at 30 seconds. Beyond that the exposure runs in bulb mode, and then something has to keep count. Guessing with an open shutter is a poor plan.
The ND1000 is where most people start, because it produces the most striking effect. For video it is almost always too strong; for glassy water it is exactly right.
The other strengths
Not sure which strength yet? Which ND filter? works from the subject to the number of stops.
Every value from ND2 to ND8192 is in the ND filter table, and the FAQ answers the common questions.