ND64: six stops
Six stops, a factor of 64: 1/125 s turns into a good half second. The ND64 is where long exposure begins without the picture losing its grip on reality. Movement goes visibly soft, and you can still tell what was moving.
- Stops6
- Filter factor64×
- 1/125 s becomes0.512 s
What this strength is good for
- Waterfalls with visible movement: Half a second to two seconds is the range where a waterfall turns silky and keeps its structure. With an ND1000 there is often nothing left but a white shape.
- Video in full sun: What the ND8 manages on an overcast day, the ND64 manages in bright light: 1/50 s with the aperture open, even with the sun up. That makes it the usual choice for drone video.
- A first taste of long exposure: A coastline under cloud, clouds drifting over a building, a busy square where people turn into streaks. All of it in the range of seconds and without bulb mode.
Calculating with ND64
Pick a shutter speed. The fields are preset to ND64.
HMINSECMS
00:00:00:512
hours : minutes : seconds : milliseconds
Exposure times with ND64
On the left the speed your camera suggests without a filter, on the right what it becomes.
| No filter | With ND64 |
|---|---|
| 1/500 | 0.128 s |
| 1/250 | 0.256 s |
| 1/125 | 0.512 s |
| 1/60 | 1.1 s |
| 1/30 | 2.1 s |
| 1/15 | 4.3 s |
| 1/8 | 8.0 s |
| 1/4 | 16.0 s |
| 1/2 | 32.0 s |
| 1 s | 1 min 4 s |
What to watch for
- This is where the tripod joins in: Half a second handheld produces nothing usable. Add a remote release, or the self-timer with a two second delay, otherwise the press of the shutter button ends up in the picture.
- Focus before you mount it: Six stops are dark enough to make autofocus hunt. Focus, switch to manual, then fit the filter. That order saves most of the soft frames.
- A slight cast is possible: Depending on the make, images drift cool or magenta. In raw that is one slider; in JPEG it is rework. A fixed white balance instead of auto at least keeps a series consistent.
If you have to pick exactly one neutral density filter and do not only want glassy water, pick the ND64. It is the most versatile of the four.
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.