ACam Viewfinder is a professional camera-department toolkit for filmmakers who work with diopters, Super 35, Full Frame, and ALEXA formats. Download free. Use Quick Diopter on set immediately. Unlock ACam Pro once when you need the full prep suite. No subscription. No account. Works in airplane mode. Free tools Quick Diopter is the on-set tool. Enter marked focus and target distance to get ideal diopter power, the nearest standard glass (+1/8, +1/4, +1/2, +1, +2, +3), a comparison table of resulting focus distances, and a BEST FIT highlight for the strength to pull from the kit. Results update as you type or tap +/-. Meters or feet. Diopter Result is for kit check. Enter marked focus and a known diopter strength to see the resulting subject distance. ACam Pro (lifetime unlock) One non-consumable purchase. Restore on any iPhone or iPad. Precision Mode is offset-aware diopter planning with DOF context. Formats include Super 35, ARRI ALEXA 35 Open Gate, Full Frame, and Large Format / VistaVision. Enter focal length, aperture, marked focus, target distance, and sensor-to-diopter-plane offset in mm. See near and far depth-of-field tolerance. Load a saved lens package to fill the fields. Depth of Field shows near, far, and total DOF for a focus mark using the format circle of confusion. Built for focus pulls and stop decisions. Hyperfocal gives hyperfocal distance and near limit for near-to-infinity coverage. Viewfinder and Split is composition planning: horizontal and vertical FOV, frame width and height at subject distance, and a place-and-rotate split-diopter line for staging notes. This is a planning overlay only, not an optical aberration simulator. Saved Lens Packages store format, focal length, diopter-plane offset, and aperture on the device. Create, edit, delete, and load them into Precision Mode. No cloud. Designed for set Offline optics math. No account, no ads, no analytics SDK. Dark cinema-kit UI. User Guide on first launch and Help on every tool. Glove-friendly +/- steppers. Treat offset-aware results as prep estimates until you verify on the glass. Who it is for Focus pullers, 1st ACs, DPs, operators, rental houses, and lens techs. What you pay for Free is Quick Diopter and Diopter Result. ACam Pro is the full prep suite as one lifetime unlock. ACam Viewfinder answers hard focus and framing questions quickly so you can move on with the shot.