Photography accumulates small problems. What shutter speed pairs with this aperture if I drop two stops? How long an exposure once I stack an ND filter? What's the depth of field at this distance and focal length? None is hard, but each one interrupts you, and the answer usually lives in some single-purpose app you have to find, open, and wait to load.
The five tools
Phototools gathers the calculators I actually reach for into one place. Right now there are five:
- Depth of Field — near and far focus limits, total depth, and the hyperfocal distance, with the circle of confusion derived from the sensor.
- Crop Factor — equivalent focal length, field of view, and equivalent aperture across sensor sizes, plus the reverse: which real focal length matches a full-frame look on your body.
- ND Filter — long-exposure shutter times and the filter strength you need, converting cleanly between stops, ND number, and density.
- Exposure Calculator — an aperture/shutter/ISO solver with priority modes and ND compensation, snapped to the one-third-stop scale and honest about when it hits a limit.
- Middle Focal Length — the unmarked focal between two marked stops, done as a geometric mean because framing scales by ratio, not by difference. It's the newest tool and still settling in.
All of it understands real sensor formats — full frame, both APS-C crops, Micro Four Thirds, one-inch, and medium format.
Nothing between you and the answer
The whole thing is client-side. No login, no account, no backend, no database — you open the page and the calculators are just there. It's an Astro static build with barely any dependencies, so it loads fast enough that using it never feels like a detour from actually shooting.
The best tool is the one already open when you need it. Convenience is what makes a utility get used at all.
The Unix idea, for cameras
The philosophy is borrowed from small command-line tools: each function does one thing and does it clearly. Put enough small sharp tools in one place and they compound into something genuinely useful, without any one of them turning into a bloated app. It's live at phototools.bystanek.com, and it grows one tool at a time — whenever I hit a calculation I'm tired of doing in my head.