iPhone · iOS 16+
Light Meter for Photographers
A professional light meter for film shooters, manual lens photographers, and studio lighting — always in your pocket.
Download on the App Store$4.99 · one-time purchase · yours forever
How it works
Open Zone Meter and the live camera view reads the light instantly. EV, colour temperature, and light condition update in real time as you move.
Tap anywhere on the preview to lock focus and exposure on a specific area — shadows, highlights, or your subject's face.
Av mode: set aperture and ISO, get shutter speed. Tv mode: set shutter and ISO, get aperture. ISO mode: set aperture and shutter, get the ISO you need.
Aperture, shutter speed, and ISO scroll like a classic analog meter. The computed value updates instantly as you adjust the other two.
Tap Save, give it a name — "Studio key light", "Golden Gate, dusk" — and it lives in your History tab, ready to share or revisit.
Features
Pure black interface that works in any lighting condition — from bright studio to dark location shoot.
Switch distance units between metres and feet in the Help tab — applies everywhere instantly.
Available in English, Japanese, German, French, Spanish, Italian, and Korean.
Expandable help on EV, aperture, hyperfocal distance, guide numbers, colour temperature, and more.
No analytics, no accounts, no subscriptions. Zone Meter collects no personal data whatsoever.
On supported iPhones, switch between all available back cameras — ultra-wide through telephoto.
Common Questions
EV (Exposure Value) is a number representing how much light hits your sensor. EV 0 is dark, EV 15 is bright daylight. Zone Meter reads live EV from your iPhone camera sensor and displays it alongside a condition label (Very Dark, Dark, Medium, Bright, Very Bright). Every EV step is one stop of light — understanding EV helps you nail exposure on film cameras, large format, and any manual camera.
Aperture Priority (Av): You set aperture and ISO, Zone Meter calculates shutter speed. Shutter Priority (Tv): You set shutter speed and ISO, Zone Meter calculates aperture. ISO Priority: You set aperture and shutter speed, Zone Meter tells you the ISO you need. Use classic drum wheels to scroll through standard aperture, shutter, and ISO values — just like an analog meter.
The ND calculator takes your meter reading (or a manually chosen base shutter speed) and computes the long-exposure time needed when using an ND filter. Presets include all standard filters: ND2, ND4, ND8, ND16, ND64, ND1000, ND32000, plus Lee Little Stopper (6 stops), Big Stopper (10 stops), and Super Stopper (15 stops). You can also input custom stop values for any filter. The app warns you when the calculated exposure exceeds 30 seconds, indicating you'll need Bulb mode.
Hyperfocal distance is the focus point that maximizes depth of field — everything from half that distance to infinity is acceptably sharp. Zone Meter's depth of field calculator shows hyperfocal distance for any lens and sensor format (Full Frame, APS-C, Micro 4/3, Medium Format, 4x5, 8x10, and more). It displays near focus limit, far focus limit, and total depth of field, plus contextual advice telling you exactly how far to refocus to bring infinity sharp. Essential for landscape photography and large format work.
Guide number (GN) is a measure of flash power: GN = Distance × Aperture. Zone Meter's strobe calculator includes presets for speedlights and studio heads from 100Ws to 1200Ws, with 8 power settings from Full to 1/128. Solve for aperture (you set distance to subject) or distance (you set aperture for desired depth of field). Guide numbers automatically scale with ISO. The fill light ratio calculator handles 1:1 through 16:1 ratios for multi-light setups.
Yes. Tap anywhere on the live camera preview to lock focus and exposure on that specific area — shadows, highlights, your subject's face, or any zone you want to meter. You can also switch between all available back cameras (0.5x ultra-wide, 1x standard, 2x, 5x telephoto on supported iPhones) to meter distant subjects without physically moving closer.
Save any meter reading or strobe setup with one tap. Name readings by location ("Golden Gate, dusk"), light setup ("Studio key light"), or anything meaningful to you. Add notes by swiping left on any saved reading. Share individual readings via Messages, Mail, or any app. Export your full history as a formatted text file. Meter readings and strobe setups are stored together, each with a type badge for quick identification.
No. Zone Meter is a one-time purchase of $0.99 with no subscription, no ads, no tracking, and no data collection. All features — live metering, ND calculator, depth of field, strobe guide numbers, history, and reference — are included. Download once, use forever.
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