Light Meter・Lux Meter vs Lux Meter

LUX METER — LIGHT LEVELS IN LUX AND FOOT-CANDLES Lux Meter is a camera-based light meter for illuminance. Aim the rear camera at a surface and read the level in lux and foot-candles, plus EV at ISO 100 — desk lighting, a grow light over houseplants, a scene for an analog camera. WHY THE NUMBER IS WORTH TRUSTING ▸ Metering method always on screen: Reflected · Point AE or Reflected · Center. ▸ Readiness comes from a 1.2-second EV window: 6 valid samples over 650 ms within a 0.16 EV spread to lock, then a 0.28 EV hysteresis against flicker. ▸ No fresh frame for 2 seconds reads Stale; unusable metadata reads Error. ▸ Moving the target, changing zoom or lens, returning from background or recalibrating restarts the window. ▸ Nothing saves or samples until the reading is valid and stable. ROOM AND WORKPLACE LIGHT LEVELS Pick the space or task, then run the five-point survey: five samples across the working plane, each held until stable, giving average, minimum, target range, observed min/average uniformity and the sampling grid. 15 practical targets in 5 groups: general office 300–500 lx, detailed office work 500–750, precision factory 750–1000, warehouse and hospital ward 100–200, corridor 100–150, classroom 300–500, library 500+, operating room 1000+, bedroom 50–150, plus kitchen, bathroom, garage, retail floor and restaurant — practical guidance, never legal certification. GROW LIGHTS, PPFD AND DLI FOR PLANTS Measure at the leaf plane of one plant and decide for that plant: pick the plant, the light source and the photoperiod, and the reading becomes a PPFD and DLI estimate in mol/m²/day. 16 plants carry daily targets: pothos and snake plant 2–4, ZZ plant 1–3, peace lily 3–6, monstera and philodendron 4–8, fern 4–7, rubber plant 5–10, fiddle leaf fig 8–12, plus bird of paradise, succulent, herbs, tomato, pepper, lettuce and strawberry. 5 light sources: sunlight, white LED, fluorescent, HPS, metal halide. The sample log marks periods it did not cover, so a thin number never passes for a full day. EXPOSURE FOR PHOTO AND VIDEO The same reading solves exposure: aperture priority, shutter priority and manual across f/1.0–f/64, 1/8000 s–60 s and ISO 25–12800 in full, ½ or ⅓ stops. Each solution gives the exact result, the nearest setting your gear really has and the residual error in stops — out of range, by how many. Manual shows Over / Matched / Under on a ±3-stop scale, and Cine turns FPS, shutter angle, ISO/EI and ND into an equivalent shutter and f-number. RECORDS AND CSV EXPORT Readings, surveys, DLI estimates, comparisons and monitoring all land in one history list — each with its method, readiness state, calibration and mode inputs. Page the archive, export to CSV. ALSO INSIDE ▸ Lock a reading; switch lux ↔ foot-candles in one tap ▸ Lux reference — 16 environments, 0.1 lx full moon to 130,000 lx direct sun ▸ EV reference — 11 scenes, −6 EV starlight to +18 EV snow ▸ A/B comparison — capture A, move to B, get the EV difference and brightness ratio ▸ Continuous monitoring — min / avg / max trend, real sampling interval, samples and missed samples, markers; background time logs as a gap ▸ Guided calibration — enter a reference value, aim at a uniform surface, wait for stable, apply the offset LIMITS AND PRIVACY A reflected-light estimate from camera exposure metadata — not an incident meter, not a PAR sensor, not a certified laboratory instrument — so it depends on the surface you aim at. The camera only measures light: no photos taken or stored, nothing uploaded, no account, and readings leave your device only in a CSV you export. Free covers the live reading and its readiness state; Pro removes ads and unlocks every workflow. Point, wait for stable, read the number — and stop guessing how much light really reaches that desk or that leaf. Terms of Use: https://zeroplay.io/docs/legal/terms-of-service Privacy Policy: https://zeroplay.io/docs/legal/privacy-policy

Lux Meter turns your iPhone into a professional light meter. Using the camera and the ISO 2720 photographic standard, it measures illuminance in lux and foot-candles in real time. Whether you're setting up studio lighting, checking your desk for eye comfort, dialing in grow lights for your plants or metering a film scene, Lux Meter gives you the numbers the pros rely on. MEASURE • Real-time lux and foot-candle readout with a one-tap unit switch • Exposure Value (EV) and color temperature (CCT in Kelvin) • Spot metering on a reticle in the middle of the camera view, or average metering of the whole frame • Live histogram, min / max / average and a live chart • A/B compare: pin a reading as the reference and see the difference in EV and percent • Lock a reading, and a low-light path that reads below 1 lux ROOM SURVEY (Premium) • Measure a grid of points across a room and see it as a heat map • Average, minimum, maximum and uniformity (U₀), checked against workplace targets for offices, classrooms, workshops, retail and corridors, or your own target • Share the result as a PDF report EXPOSURE CALCULATOR • Set two of aperture, shutter and ISO — it solves the third • ND filter, exposure compensation and a Sunny 16 helper • Cinema mode with frame rate, shutter angle and the 180° rule, plus a depth-of-field calculator (Premium) GROW LIGHT (Premium) • Turn a reading into PPFD and Daily Light Integral (DLI) for sunlight, LED, HPS, metal-halide or fluorescent light • Photoperiod setting and a light guide for low- to high-light plants TARGETS & FEEDBACK • Presets for reading, office, photography, film, plants and aquariums • Target band with an in-range indicator • Optional haptic and audio meter tick that speeds up as the light gets brighter CALIBRATION • Separate calibration for the front and back cameras, with raw and calibrated values side by side • Manual multiplier, plus multi-point calibration across the whole range (Premium) HISTORY & REPORTS • Save single readings or record the light over time, with notes and an optional location tag • Chart and statistics for every recording • PDF reports and CSV export (Premium) LUX METER PREMIUM A one-time purchase, no subscription. Unlocks Room Survey, PDF reports, unlimited history and recording time, CSV export, multi-point calibration, Grow Light, cinema mode and depth of field. MORE • 11 languages with instant in-app switching • Dark design with a light mode, grid overlay, brightness pin and keep-awake A note on accuracy: iOS does not give apps access to the ambient light sensor, so Lux Meter uses camera-based reflective metering (ISO 2720). For the best results, calibrate once against a reference meter. Measure light like a pro. Download Lux Meter.