Thea — Light Meter + Film Log

Thea is a light meter for photographers who care about exposure.

Hold up your iPhone, point it at what matters, and Thea gives you a reading you can trust. Built for film and digital, in the studio or out on the street, and tuned to the cameras, lenses, and film stocks you actually shoot with.

Thea is built around your gear. Add the cameras you own, the lenses they wear, and the films you keep loaded. Each camera with its own shutter range, aperture range, ISO range, and stop increments. From then on, the meter speaks your camera's language. If your Pentax K1000 only goes to 1/1000, Thea won't suggest 1/4000. If your XA opens to f/2.8, that's where the dial starts.

Metering stays out of your way. Point at what you want to expose and the reading is already there. Lock it when you want to study the numbers without things shifting. Switch between Aperture Priority, Shutter Priority, Manual, and EV modes as the situation calls for it, and dial in full, half, or third stops.

Thea treats a roll of film the way you do, as a thing with a beginning, a middle, and an end. Load it, log frames as you shoot, and watch the counter tick toward the last exposure. A reference photo is saved with each frame automatically, and you can add a quick note or a location if you want. When the roll comes out of the camera, mark it In Development. When the scans come back, send it to the archive. The whole history is right there, ready to flip through.

Bundled with Thea is a library of nearly a hundred film stock presets. Portra, Tri-X, T-Max, HP5, Velvia, Acros, Delta, Vision3, CineStill, and many more. Box speeds and color types are already filled in, so loading a fresh roll is one tap. Push or pull the stock and Thea adjusts the readings to match.

In the field, you'll usually have a camera in one hand and a meter in the other. Thea is designed for that. A one-hand mode brings every control into thumb reach so you can adjust a reading without putting the camera down. The screen stays awake through long outdoor sessions. Haptics confirm every action so you don't have to look down at the phone. Every part of the interface, from the typography to the timing of a transition, has been carefully considered, then quietly polished, until the app fades out of your way.

Thea runs entirely on your device. No accounts to make. No analytics sent home. No ads. Camera access is required to meter. Location is optional, and only used if you choose to attach it to a shot log.

Made with love by a photographer, for photographers.