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After the shoot · Developing & darkroom

Shutter Tester

Shutter tester: hold the phone’s microphone close to the camera, fire the shutter once, and it times the gap between the opening and closing sounds. You get the measured milliseconds, how many stops off the marked speed it is, and a verdict — normal, running slow or fast, needs servicing, or possibly sticking (based on the repair-trade rule of thumb of ±1/3 and ±1/2 stop; for reference only). Reliable from 1 s to 1/60; faster speeds can’t be measured by sound, so no number is shown. If an SLR makes more than two sounds (mirror and so on) it gives no reading and suggests mirror lock-up. Test speed by speed into a report saved on the device, re-test a single speed, or export the report as a poster. Fully on-device: the recording is analysed in memory and never saved or uploaded. Free.

When it helps

At a glance

Where to find itTools tab → Shutter Tester
CategoryAfter the shoot · Developing & darkroom
PlatformsiOS / Android / HarmonyOS (native) (coming soon)

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“Shutter Tester” is one of the 41 photography tools in Optaxis. Coming to iOS, Android and HarmonyOS (native) at the same time, expected between late December 2026 and early January 2027; once live, search for “光轴 Optaxis” in your app store to download.