An 8-hour overnight timelapse sounds like a manageable single card until the shot count is actually worked out: at a 20-second interval, that's 1,440 individual frames, each one a full RAW file. Multiply file size by shot count and the total can run past what a single card holds — a discovery that's far better made in advance than at 3am when the card fills up and the sequence stops mid-shoot.
Why shot count grows faster than intuition suggests
Total shots is duration divided by interval, and both numbers tend to be larger for timelapses than for ordinary shooting: intervals are often measured in single-digit seconds, and durations in hours. An 8-hour star trail session at a 20-second interval produces 1,440 frames; a 12-hour cloud timelapse at a 10-second interval produces 4,320. Neither number is obvious from "I'm shooting for a while at a short interval" without actually multiplying it out, which is exactly why storage runs out unexpectedly more often on timelapses than on any other kind of shoot.
RAW vs. JPEG changes the total by roughly 3x
File size per frame is the other half of the equation, and RAW files from a modern full-frame sensor typically run 25–45MB each, compared to roughly 8–15MB for a JPEG at the same resolution. That difference compounds directly with shot count: the 1,440-frame overnight sequence above needs about 49GB in RAW (at roughly 35MB per file) versus about 17GB in JPEG (at roughly 12MB per file) — nearly three times the storage for the same shoot, before any other setting changes. RAW keeps more room to fix exposure and white balance in post, which matters more for a scene with big brightness swings (sunset into night) than for a static subject like slow-moving clouds in even light.
A concrete planning example
The 12-hour, 10-second-interval cloud timelapse above comes out to roughly 127GB in RAW — more than a 64GB card can hold, and tight even on a 128GB card once other files on it are counted. Working that out before the shoot means one of three fixes gets chosen deliberately: shoot JPEG instead of RAW for a scene that doesn't need the extra dynamic range, lengthen the interval if the cloud motion can tolerate it, or bring a larger card. Any of those is a reasonable choice — the problem is only when none of them gets chosen because the total was never calculated.
Storage is only half the constraint
Working out card capacity doesn't cover everything a long timelapse burns through — battery life is the other hard limit, and a camera drawing power for 8 or 12 hours straight generally needs a battery grip, a dummy-battery AC adapter, or a USB power bank rather than relying on a single battery. A short interval also pushes closer to a card's sustained write speed, and a slower card can start dropping frames or stalling mid-buffer well before it's actually full — worth testing at your planned interval before an overnight shoot, not during one.
Using the calculator to check before you commit a card
ExifLens's Time-Lapse Calculator (/tools/timelapse-calculator) takes your planned shot count (or interval and duration, which determine it) along with an estimated file size per photo, and returns the total storage needed directly — no manual multiplication required. Running the numbers before an overnight or multi-hour shoot means choosing RAW vs. JPEG, adjusting the interval, or picking a card size becomes a decision made at home with options, rather than one forced in the field when storage runs out.
Field checklist
- Multiply interval and duration into an actual shot count before estimating storage — the total is usually larger than it feels.
- RAW typically needs about 3x the storage of JPEG for the same shot count — decide which you need based on how much post-processing latitude the scene requires.
- Leave real headroom on the card (not just enough to exactly fit the estimate) for a metadata overhead and any format variance between shots.
- Check your card's sustained write speed against your interval — a short interval on a slow card can drop frames before it's technically full.
- Plan external power for anything past a couple of hours; running out of battery ends the sequence as abruptly as running out of storage.