Cutvey Meter, the facts

What it reads

• Color temperature in kelvin and tint (green to magenta), live, from the camera's auto white balance (AWB) or from a gray card filling the frame, one tap apart. The scale runs from 1,800 to 12,000 K.
• How steady each reading is: HIGH, MEDIUM or LOW. DIFFICULT SOURCE when the light flickers, when a gray card is lit by two colors at once, or when the color is past what the camera can read.
• A RAW MEASUREMENT when you hold LOG, on any camera that offers RAW (never the front camera): kelvin and Duv from the sensor's own pixels.
• The light level in lux or foot-candles, worked out from the exposure assuming an 18% gray surface.
• The gap between two lights: pin one with REF, or type a target from 2,000 to 10,000 K, and the card shows the difference in kelvin, mired and tint and the CTO or CTB that closes it, never more than two sheets. LEE numbers by default, Rosco or both on request. MATCH shows within 5 mired. Stops shows the key-to-fill difference.
• A live ND figure for your ISO, stop, shutter and frame rate, from ND 0.3 to 2.1, or it solves for the ISO, the stop or the shutter instead.
• Flicker: banding from a dimmed LED or a lamp on the mains, with the nearest flicker-safe shutter for 50 or 60 Hz power and a USE button.
• The sun's path over the live camera, with sunrise, solar noon and sunset and their bearings, and golden hour (+6° to −4°) and blue hour (−4° to −8°) for today and up to two more dates.
• Meter Map: any place on any day, with the sun's path in 2D or 3D, a stand-in's shadow at every hour and pins for your readings. Share a plan as a picture, with or without the location.
• A golden hour alert 15 minutes before each golden hour and the evening blue hour, on iPhone, iPad and Apple Watch.
• Meter and Sun controls for Control Center, the Lock Screen and the Action button (iOS 18).
• A library of every logged reading with its frame. Compare any two, share one with its picture.
• A calibration offset for each lens, in kelvin and tint. Logged readings stay uncorrected.

What it does not do

• It reads three color channels through a camera. It is no spectrometer: it shows no spectrum and no color rendering figure (CRI, TLCI, TM-30), and a steady light with a spiky spectrum can read HIGH and still be off.
• Flicker detection catches banding at video frame rates. It can miss a light locked to an exact multiple of your frame rate, and it does not measure a flicker's frequency or percentage.
• The lux figure is a reflected reading converted from the exposure. It is no incident reading and no flash meter.
• Calibration is one offset per lens, so it cannot follow an error that changes from warm to cool light.
• The plus or minus green suggestion is approximate, and the app says so.
• No export of the whole log, no iCloud sync, no home screen widgets and no Siri or Shortcuts actions.
• No Family Sharing for the purchase, and no free tier: the app opens after the purchase or a Cutvey sign-in.
• This website never asks where you are.

41 languages

The app follows your device's language. To change it, open Settings in the app and pick one under LANGUAGE.