What M43 Lens Database is
M43 Lens Database is a companion for Micro Four Thirds photographers. At its heart is a database of MFT lenses you can browse, filter, and track — mark what you own, see your kit's coverage and stats in My Kit, keep a shot log of what you photographed and what you learned, and attach your own photos to lenses. A depth-of-field calculator with a visual diagram is built in, but the lens library and your collection are the main event.
Lenses & the database
How many lenses are in the database?
Over 80 Micro Four Thirds lenses from Panasonic, OM System / Olympus, Sigma, Voigtländer, and more, each with real specs — focal range, aperture, weight, size, weather sealing, and image stabilization. The database grows with updates.
A lens I own isn't in the database. Can I add it?
Yes. Tap the + in the Lens Database toolbar to add any lens — legacy, adapted, or third-party. Once added it works everywhere a built-in lens does: depth-of-field tools, comparison, and the shot log.
Can I edit or delete a lens I added?
Yes. Custom lenses are fully editable — tap the Edit (pencil) action on the lens card to fix a name, correct a spec, or delete it. Built-in database lenses are read-only. (Deleting a custom lens also removes its shot notes and photos.)
The keyboard changed a lens name I typed. How do I fix it?
As of version 2.1.2, autocorrect is turned off in the lens-name field, so proper-noun names like "Laowa" stay as you type them. If an older entry got mangled, just edit the lens and retype the name.
Why does a magnification number here differ from the manufacturer's sheet?
The app lists the true Micro Four Thirds magnification. Many spec sheets headline the "35mm-equivalent" figure, which is double the native number. We store the native value so the database is internally consistent.
What does the "I/II" badge mean?
It marks a lens whose Mark II version is optically identical to the one listed — one entry covers both, so you don't need to pick.
My Kit & ownership
How do I mark a lens as owned?
Tap the heart on any lens card. Owned lenses feed My Kit — your collection dashboard with totals, a focal-coverage chart, a brand breakdown, and a heat map of which lenses you shoot most. Reach My Kit from the bag icon in the Lenses toolbar once you own at least one lens.
Shot notes (the shot log)
What are shot notes for?
To remember what worked. Each note links to one of your lenses and records your settings, what you were going for, the result, and what you learned — with the depth-of-field math calculated for you. Notes are searchable across every field.
Can I attach a photo to a note?
Yes — one photo per note, picked from your library. A copy is stored inside the app, so the note keeps its reference frame even if you later delete the original from Photos.
Can I get my notes out of the app?
Yes. Export all notes (or a date range) as CSV, JSON, or Markdown, and share any single note to Messages, Mail, Files, or AirDrop.
Photos on lenses
How do I add photos to a lens?
Tap the Photos icon on any lens card to open its gallery, then add photos from your library — product shots, MTF charts, or pictures from your own copy. You can add several per lens. The icon turns blue once a lens has photos, so you can see which lenses you've documented at a glance. This works on every lens, whether or not you own it.
Will adding photos prompt for Photos access?
No. The picker doesn't require Photos-library permission — you choose exactly which images to bring in.
Depth-of-field tools
How is depth of field calculated?
Using a Micro Four Thirds–specific circle of confusion (0.015 mm), so the near/far limits and hyperfocal distance reflect the MFT sensor rather than a full-frame assumption. The visual diagram draws the in-focus zone to scale and updates live as you change focal length, aperture, or focus distance.
Can I compare two lenses?
Yes. From the DOF tools, pick two lenses and compare them side by side — each with its own focal length and aperture, sharing a focus distance.
Your data, backup & privacy
Where is my data stored?
Entirely on your device. Your owned lenses, custom lenses, shot notes, and photos live in the app — there's no account, no sign-in, and nothing is uploaded to us.
Does the app track me?
No. M43 Lens Database has no analytics or tracking and asks for no Photos-library permission.
How do I back up or move my data to a new phone?
Your data is included in your normal iPhone backup (iCloud or your computer). Restoring that backup, or transferring to a new device, brings your collection, notes, and photos with it. (A dedicated custom-lens export/import is on the roadmap for an extra off-device copy.)
Requirements & contact
What do I need to run it?
An iPhone on iOS 17 or later.
I have a question, a bug, or a lens to suggest.
Get in touch at developer@digtek.app — it reaches the person who built the app. Lens suggestions are welcome; several database additions have come straight from user feedback.