ProFilm Meter

ProFilm Meter is the most complete light meter and exposure toolkit for film photographers. From 35mm to 20x24 inch Ultra large format, dry plates to RA4 reversal, it handles every calculation you'd normally reach for three separate tools to solve — all offline, all in real time.

LIGHT METERING
Your phone's camera becomes a precision reflected-light meter. Choose spot, center-weighted, or average metering and dial in exposure with ⅓-stop, full-stop, or any combination of increment sets running simultaneously. A live RGB histogram keeps highlight and shadow zones in view at all times.

Native per-frame ISO, shutter, and aperture capture at ~10 fps
Multi-point metering: average 2–4 scene readings into one exposure value
Tap-to-focus and multi-lens camera selection
Adaptive EV smoothing adjusts for scene changes automatically
Screen stays awake during active metering sessions

CALIBRATION
Two-point guided calibration locks each camera to a trusted reference. After calibration, a fine-tune step lets you match any external meter in ⅓-stop increments. Uncalibrated cameras are gated with a full-screen prompt so you never shoot on an unmeasured body.

FILM STOCKS & RECIPROCITY
An on-device film stock library covers 35mm, 120, and large format emulsions — including the full Zebra Dry Plate collection. Every stock carries its own reciprocity profile. Eight built-in profiles (Acros II, T-Max, HP5+, Portra, Fomapan, Zebra, and more) plus full custom profile creation, including Schwarzschild p-factor and optional threshold. Add custom film formats and reciprocity profiles inline, without leaving the film stock screen.

COMPENSATIONS
Reciprocity failure — corrected automatically for exposures beyond threshold
Bellows compensation — calculated stop-for-stop from draw and focal length
RA4 Color Reversal — estimates scene color temperature and gives you Mired-shift filter corrections for color positives; works in both ambient and flash mode
Spectral sensitivity — metering coefficients adjusted for panchromatic, orthochromatic, and blue-sensitive emulsions
Lens filters — ND (1–10 stops), polarizer, yellow/orange/red/green contrast filters, R72 and deep IR, plus custom filters
Positive/reversal process — +0.5 stop compensation, auto-enabled for tintype stocks
UV/environmental compensation — adjustable for altitude and atmospheric conditions
IR Light Estimator — dedicated tool for infrared exposure estimation

FLASH
Flash metering detects incident flash via fast polling with peak-hold and sticky arming. A built-in flash trigger supports Optical Slave (fires the LED torch to trip slaved units) and Cable Sync (audio click for USB-C to PC-sync adapters).

VIEWFINDER
A lens-independent viewfinder zoom gives consistent framing regardless of which physical lens the phone uses. Overlay your chosen film format frame lines and compose like you're looking through a director's viewfinder.

FIELD JOURNAL
Save any exposure to the journal with one tap. Each entry records ISO, aperture, shutter speed, EV, reciprocity correction, RA4 and spectral corrections, GPS coordinates, and a cropped preview photo. Entries are exportable and shareable.

EXTRA TOOLS
Depth of Field Calculator — for any format and focal length
Zebra Exposure Guide — zone-system reference for dry plate work
Alternative Processes Meter — cyanotype, platinum, salt print, and more
Step Wedge Tool — exposure planning for contact printing
Rolling Shutter Calculator — flash sync safety for focal-plane shutters

20 FILM FORMATS
35mm · 6×4.5 · 6×6 · 6×7 · 6×9 · 4×5 · 5×7 · 8×10 · 9×12cm · 10×10 · 10×12 · 11×14 · 12×12 · 13×18cm · 20×24 · Sixth Plate · Quarter Plate · Half Plate · Whole Plate · custom dimensions

7 LANGUAGES
English · Slovenian · Spanish · French · German · Japanese · Simplified Chinese

PRIVACY
All metering and calculation runs entirely on-device. No account required. No data leaves your phone.