Depth diffraction lab

Depth of field is geometry, not a number. Most calculators hand you two figures and a shrug. Depth Lab draws the light path — and then lets you grab it. THE DIAGRAM IS THE CONTROL Drag the subject sideways and the sharp band slides with it. Pull the focus plane and the near and far limits follow in real time. Drag the aperture ring and the cone of light visibly narrows. No form to fill in: the drawing is the input, and six readings above it update every frame — near limit, far limit, total depth, hyperfocal distance, magnification and frame width at the subject. Lock two of the three controls and the third becomes an answer: name the near limit you need, and the app tells you where to focus. TWO LIGHT PATHS AT ONCE Tap A|B and the screen splits: one scene at two settings, sharing a distance scale, with a difference table reading out near, far, total, hyperfocal, magnification and diffraction. How much do you gain from f/1.4 to f/4? Copy A into B, change one thing, and see the cost in centimetres. A RULER YOU CAN READ The Scale tab puts the optical range on a logarithmic ruler from 0.1 m to infinity, with focus, near, far and hyperfocal marked and the sharp band filled in. The bokeh ladder shows one background object at eight distances as discs sized by their real blur. A framing panel overlays other sensor sizes to show what the lens truly sees; the diffraction bar marks where this sensor softens — around f/6.5 at 45MP full frame. SOLVE FOR WHAT YOU WANT Four inverse solvers. Give a near and far limit and it finds the aperture and focus distance that reach both, then states the residual instead of hiding it: f/13 at 2.88 m covering 2.00 to 5.17 m — seventeen centimetres more than you asked for. Ask for infinity and it returns the hyperfocal distance and the aperture that reaches it. Ask for 1:1 and it gives working distance, frame coverage and the light extension costs. Exposure pairs stay on one EV through a three-stop ND. HONEST ARITHMETIC Exact thin-lens equations, not the Hs/(H+s) shortcut that drifts thirty percent at macro range. Cross-format conversion uses the real sensor diagonal: 35 mm on APS-C becomes 53.7 mm on full frame, matching to a tenth of a degree. Where physics is only a rule of thumb — safe shutter, close-up depth — the app says so beside the number. YOUR GEAR, YOUR PRESETS Eight bodies from 1-inch to 100MP medium format and twelve lenses ship built in; add your own with focal length, aperture range and closest focus. Save any setting as a preset, and export a one-page PDF parameter sheet when you want it on paper. NOTHING LEAVES THE PHONE No account, no analytics, no advertising, and the app never opens a network connection. It requests no permissions at all — not the camera, not the photo library, not location. Gear and presets stay in the app's own folder. SOMETHING ON SCREEN FROM THE START Six sample presets — street, portrait, hyperfocal, macro, group, APS-C walk — ship with the app, so every chart has something to show. Clear them in one tap. Focus is a decision you make before the shutter. Depth Lab lets you see it first.

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