Overview
ISO 15781:2019 specifies standardized methods to measure and report shooting time lag, shutter release time lag, shooting rate, and start‑up time lag for digital still cameras - including camera modules in phones and tablet computers. The standard defines key terms (e.g., shooting time lag, shutter release time lag, start‑up time lag, shooting rate) and provides two principal measurement approaches: one that uses internal control signals and one that derives timing without access to the camera’s internal electronics.
Key topics and requirements
- Definitions and scope: Clear definitions for timing metrics (shooting time lag, shutter release time lag, start‑up time lag, shooting rate) and test limits (excludes AF speed below recommended illumination and AF accuracy).
- Measurement methods:
- Internal control method - uses control signals inside the camera to start/stop timing.
- External (non‑intrusive) method - determines timing values using observable outputs without opening the device.
- Test conditions:
- Recommended illumination: 500 lx to 5 000 lx (daylight or tungsten; compatibility with ISO 7589).
- Test chart and mounting: camera on a stable tripod, chart height 80 ±10 cm, chart geometry and surrounding 18% grey area.
- Battery, memory card, flash, image stabilization and other settings must be controlled and reported.
- Measurement procedure and reporting: Procedures for start‑up time, shooting time lag, shutter release time lag and shooting rate are described, plus required reporting formats (see Clause 6 and informative Annexes for examples).
- Supporting material: Annexes cover timing devices, measurement accuracy estimation, setups for continuous autofocus cameras, and reporting examples.
Applications and who uses this standard
ISO 15781:2019 is used by:
- Camera and smartphone manufacturers for product design, firmware tuning and quality assurance to quantify shutter lag and responsiveness.
- Test laboratories and certification bodies to produce repeatable, comparable performance data.
- Product reviewers and technical journalists for objective camera speed comparisons.
- R&D and firmware engineers focusing on autofocus, exposure pipeline and buffer throughput optimization.
- Procurement and compliance teams specifying performance requirements for imaging modules.
Practical benefits include reliable measurement of capture responsiveness, consistent shooting‑rate evaluation for burst photography, and standardized start‑up time verification for user experience benchmarking.
Related standards
- ISO 7589 (illuminants for sensitometry) - referenced for acceptable test illumination.
- ISO 12233 - resolution test charts recommended for focus verification and image assessment.
Keywords: ISO 15781, digital still camera testing, shooting time lag measurement, shutter lag standard, start‑up time lag, shooting rate, camera module performance.
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