Long Exposure Photography — Settings & Workflow
Silky waterfalls, empty streets, streaking car lights: all the same trick — keep the shutter open long enough that motion becomes blur. Here's the exact workflow, with the math at each step.
The workflow, step by step
- Compose and focus — focus, then switch to manual. Autofocus at f/11 in the dark will hunt.
- Set aperture + ISO: f/8–f/11 for depth of field (see landscape DoF), ISO 100 always.
- Meter without the filter — note the shutter speed your meter wants (e.g. 1/60 s at f/11).
- Decide your target time — how blurred do you want the motion?
- Find the ND stops: stops = log₂(target ÷ base). 1/60 s → 15 s needs log₂(900) ≈ 9.8 stops → an ND1000 (10 stops) gets you to ~17 s.
- Mount the filter, set bulb (or the computed speed), release — remote release or 2-second timer, never your finger.
- Check the histogram — if highlights clip, add a stop of ND or shorten; the first frame is a test frame.
Which effect needs which exposure
| Effect | Typical time | ND needed (from 1/60 s base) | Notes |
|---|---|---|---|
| Slight motion in water | ¼ – 1 s | ND8–ND16 (3–4 stops) | Mist starts; keep rocks crisp |
| Silky waterfall | 2 – 8 s | ND64–ND1000 (6–10 stops) | The classic look |
| Empty streets / crowds gone | 15 – 60 s | ND1000+ (10+ stops) | People vanish; car lights streak |
| Light trails | 10 – 30 s | ND1000 (10 stops) | Night — often no ND needed |
| Clouds streaking | 1 – 5 min | ND1000+ stacked | Check for sensor hotspots |
Run your own numbers with the ND filter calculator or read straight off the long exposure chart.
The three mistakes that ruin long exposures
- Shooting at f/22 "for sharpness." Diffraction beats the DoF gain; f/8–f/11 is sharper. If you need more depth, focus-stack.
- Trusting the filter's rated density. Budget NDs can be off by a third of a stop — meter through the filter when possible, or bracket.
- Camera shake you can't see. Tripod + remote + mirror lockup (DSLRs) + switch off image stabilization on the tripod (it can hunt and add micro-shake).
Long exposure math, plainly
Each ND stop doubles the shutter time: 1/60 → 1/30 → 1/15 → 1/8 → ¼ → ½ → 1 s → 2 s → 4 s → 8 s → 16 s → 32 s. Ten stops (ND1000) turns 1/60 s into ~17 s. That's the entire calculation — the calculator and chart just do it for you, including the awkward fractions.
Related tools & guides
ND Filter Calculator
Exact shutter for any filter and base exposure.
Open →ND Filter Long Exposure Chart
The full pre-computed table, printable.
Read →Shutter Speed Chart
Waterfall times and everything else in one table.
Read →Long exposure FAQ
Do I need a 10-stop ND, or is 6 enough?
It depends on the effect. ND64 (6 stops) takes 1/60 s to ~1 s — fine for misty water. ND1000 (10 stops) reaches 15–30 s — the crowd-removing, cloud-streaking territory. Most photographers own both; a variable ND covers the middle.
Why is my long exposure purple or green?
Color cast from the ND filter — cheap filters shift toward magenta/green. Fix in post with a white-balance eyedropper on a neutral area, or buy higher-quality glass. Stacking two cheap filters worsens the cast.
Can I do long exposures on a phone?
Modern phones have built-in long exposure / light-trail modes that stack frames instead of opening the shutter — different technique, same look. The composition and subject advice here applies identically.