Focara Lens: DoF & Exposure

Focara Lens is a calculator, not a camera app. It does the optics maths you used to scribble on the back of a lens cap — depth of field, hyperfocal distance and exposure equivalence — and it does them with the real circle-of-confusion figures for your sensor. Built around a clean blueprint layout: paper-white, one decisive blue, hairlines instead of clutter. Four tabs, swipe between them. DEPTH Dial in focal length, aperture and focus distance, then pick your sensor — full-frame, APS-C (1.5x and 1.6x), Micro 4/3 or 1-inch. Focara returns the near and far limits, the total depth, how it splits in front of and behind the subject, and the hyperfocal distance. A drawn distance scale shows the in-focus zone at a glance, infinity included. HYPERFOCAL The single most useful number for landscape and street work. Set focal length, aperture and sensor; read the hyperfocal distance. A side table sweeps every common f-stop so you can see exactly what stopping down buys you. EXPOSURE A reciprocity engine. Lock the brightness of a base exposure, change shutter, aperture or ISO, and Focara solves the matching value to keep the exposure constant. There is also a stops-between helper: drop in two apertures, two shutter speeds or two ISOs and get the difference in stops, brighter or darker. REFERENCE Cheat-sheet cards you will actually reach for — sensor sizes and crop factors, the full-stop aperture, shutter and ISO series, the Sunny-16 rule, and the circle-of-confusion values behind the depth maths. Save the rigs you shoot most. Your favourite portrait setup or run-and-gun street combo is one tap away, kept on the device. WHAT IT IS NOT No viewfinder, no filters, no login wall. Focara never asks for a permission, never reaches for the network, and never makes a sound. It is a quiet reference tool that opens fast and stays out of the way. The formulas are the textbook ones, computed in a self-contained optics core and rounded only for display — so the answer on screen is the answer, not an estimate dressed up.