Set-up discipline
Long exposure rewards order and repetition. Do it the same way every time and the failures disappear.
- Manual (M). You'll be changing shutter constantly while aperture and ISO stay put — no fighting with Exposure Comp.
- Manual Focus (MF). Zoom to maximum focal length, magnify, focus on something non-moving, then zoom back to frame. Autofocus between steps is how frames get lost.
- Tape the focus. A strip of gaffer tape across the focus barrel (and the zoom barrel on a zoom) holds both until you remove it.
- Single-shot drive unless you're bracketing.
- Compose, meter and focus before the filter goes on — you can't see through a 10-stop.
- Cable release / remote and a solid tripod are not optional items.
Choosing the exposure length
Longer is not automatically better. In a tested sequence — 4 s, 15 s, 29 s of the same scene — the long-exposure effect was strongest at 4 seconds. Past that, movement averaged out into featureless smoothness.
- Useful working range to start from: 1/2 s to 30 s.
- Vary the exposure two ways, and they give different results: (1) change the time and compensate with aperture/ISO to hold the same exposure; (2) change the time and let the frame deliberately over- or underexpose.
- Spend time with a scene that's worth it: vertical and horizontal, different points of view, different lenses — and several exposure lengths of each.
Subject and framing
- Something in the frame must be static and sharp. The moving element is the medium, not the subject.
- Wide vs telephoto changes the whole character: wide includes the sky's movement, long isolates a single moving passage.
- Environmental conditions are half the result — cloud speed and direction, wind, tide, water state. A featureless clear sky records as nothing at 30 s.
- Colour or monochrome is a decision to make before the frame, not after.
Eye snags watch for these
Eye snags are the small unintended items that grab a viewer and drag them away from where you wanted them. Long exposure makes them easy to create and easy to miss, because you're absorbed in the technique.
- A bright object at the frame edge — foam, a lit window, a white sign, a gull.
- A blown highlight in a corner, or an intrusion at the bottom of the frame.
- Something that moved just enough to become a smear rather than a shape.
- A leading line that leads out of the frame instead of in.
- The plan can be perfect on paper — a Z curve, a rock frame, a vignette to hold the eye — and still fail. Check the frame, not the plan.
Habit: after each frame, look at the four edges and the four corners before anything else.
Filter notes
- Cheap ND casts a colour shift; quality glass shifts less. Correct it in RAW, or choose better glass.
- Light leaks are the long-exposure bugbear — cover the viewfinder, and check where a slot-in holder meets the lens.
- Stacking filters (e.g. 10-stop + 6-stop + 3-stop soft graduated) is normal for daylight work; expect vignetting at wide focal lengths.
Consolidated from references: Kent DuFault, The Complete Guide to Long Exposure Photography; Flavio Spedalieri, Long Exposure Photography presentation.