JustCreature · JustCreature · Feb 17, 2026 · Feb 17, 2026 · Feb 17, 2026 · Feb 17, 2026
diff --git a/CLAUDE.md b/CLAUDE.md
@@ -6,6 +6,41 @@ This file provides guidance to Claude Code (claude.ai/code) when working with co
 
 Film Photography Tracker is a Progressive Web App (PWA) for tracking film photography metadata. Built with React 18, TypeScript, Vite, and Material-UI, it helps photographers record and organize shots with exposure details, location data, and camera information.
 
+## Feature Documentation Process
+
+When completing work on a feature or making significant changes:
+
+### Completed Features
+1. **Document the feature** in `docs/features/done_F-{n}.md` where `n` is the next sequential number
+2. **Include in the documentation:**
+   - Feature overview and key components
+   - Technical details (files changed, new APIs, data models)
+   - User benefits and use cases
+   - Testing coverage
+   - Commits included
+   - Migration notes (if applicable)
+   - Future enhancement ideas
+3. **Naming convention:** `done_F-1.md`, `done_F-2.md`, etc.
+4. **Delete task plans** from `docs/tasks/todo/` once implemented
+
+### Planned Features
+1. **Create plan** in `docs/tasks/todo/plan_F-{n}.md` for future features
+2. **Include in the plan:**
+   - Problem statement
+   - Proposed solution
+   - Implementation steps
+   - Benefits and trade-offs
+   - Effort estimate
+3. **Naming convention:** `plan_F-5.md`, `plan_F-6.md`, etc.
+4. **Move to done_** once implemented (renumber if needed)
+
+**IMPORTANT for Claude Code plan mode:** When entering plan mode, ALWAYS write the final plan to `docs/tasks/todo/plan_F-{n}.md` (NOT to `~/.claude/plans/`). This ensures plans are tracked in the repository.
+
+### Feature Numbering
+- Start from F-1 and increment sequentially
+- Completed features use `done_` prefix
+- Planned features use `plan_` prefix
+
 ## Key Commands
 
 ### Development

diff --git a/docs/features/done_F-1.md b/docs/features/done_F-1.md
@@ -0,0 +1,254 @@
+# Feature F-1: Advanced Lens Management & Smart Focal Length System
+
+**Status:** ✅ Completed
+**Branch:** `new_features`
+**Completion Date:** 2026-02-17
+
+## Overview
+
+This feature introduces comprehensive lens management capabilities and intelligent focal length tracking with dynamic UI controls that adapt to lens type (prime vs zoom).
+
+## Key Components
+
+### 1. Lens Management System
+
+#### Lens Model
+Added new `Lens` interface to support both prime and zoom lenses:
+
+```typescript
+interface Lens {
+    id: string;
+    name: string;
+    maxAperture: string;           // e.g., "f/1.4", "f/2.8"
+    focalLength?: number;           // For prime lenses (e.g., 50)
+    focalLengthMin?: number;        // For zoom lenses (e.g., 24)
+    focalLengthMax?: number;        // For zoom lenses (e.g., 70)
+    createdAt: Date;
+}
+```
+
+#### Lens Management Screen
+- **New Component:** `src/components/LensManagementScreen.tsx`
+- Full CRUD operations for lens library
+- Validation: Prevents creating lenses that are both prime AND zoom
+- Auto-disabling fields: Prime/zoom fields disable each other
+- Material-UI Alert component for inline validation errors
+- Grid layout with lens cards showing:
+  - Lens name
+  - Max aperture
+  - Focal length (single value for prime, range for zoom)
+
+### 2. Exposure Index (EI) Override
+
+Added ability to override film ISO on a per-exposure basis:
+
+- New `ei` field in `Exposure` type (optional number)
+- EI selector in camera settings with:
+  - "Use film ISO" default option
+  - Preset values (50, 100, 200, 400, 800, 1600, 3200, 6400)
+  - Custom value input for non-standard EI values
+- Exports include EI data for EXIF writing
+
+### 3. Smart Focal Length Slider
+
+#### Reusable Component
+- **New Component:** `src/components/FocalLengthSlider.tsx`
+- Extracted from duplicated code in CameraScreen and DetailsScreen
+- Saved ~220 lines of code through component reuse
+
+#### Dynamic Behavior Based on Lens Type
+
+**No Lens Selected:**
+- Full slider range: 1-200mm
+- Step: 1mm
+- Fully active and editable
+- Manual input field accepts any value
+
+**Prime Lens Selected (e.g., 50mm):**
+- Slider locked at lens focal length
+- Disabled with grey styling
+- Label shows "(Prime lens - fixed)"
+- Manual input field disabled
+- Auto-sets to lens focal length when lens is selected
+
+**Zoom Lens Selected (e.g., 80-200mm):**
+- Full slider range visible (1-200mm)
+- Movement constrained to zoom range (can't slide below 80mm or above 200mm)
+- Step: 5mm for easier zoom adjustment
+- Label shows zoom range: "(80-200mm zoom)"
+- Manual input field constrained to zoom range
+- Auto-sets to midpoint when lens is selected (rounded to nearest 5mm)
+
+#### Slider UI Features
+- Common focal length marks: 1, 28, 50, 85, 135, 200
+- No "mm" suffix on labels (cleaner look)
+- Value indicator tooltip while dragging
+- Smooth constraint handling (can't drag outside allowed range)
+
+### 4. Mid-Roll Lens Changes
+
+Users can now change lenses mid-roll:
+
+- **Film Roll Level:** `currentLensId` field tracks active lens
+- **Exposure Level:** Each exposure stores its own `lensId`
+- Lens selection in camera settings updates film roll's current lens
+- Lens change dialog accessible from camera screen
+- New exposures automatically use currently selected lens
+
+### 5. Aperture Filtering by Lens
+
+Aperture dropdown now respects lens maximum aperture:
+
+- If lens has max aperture of f/2.8, only shows f/2.8 through f/22
+- Prevents selecting physically impossible apertures
+- Works in both camera screen and details/editing screen
+
+### 6. Enhanced Export/Import
+
+Updated metadata export format to v2.0.0:
+
+```json
+{
+  "version": "2.0.0",
+  "filmRoll": {
+    "ei": 400,
+    "currentLensId": "lens-id"
+  },
+  "exposures": [
+    {
+      "ei": 400,
+      "lensId": "lens-id",
+      "lensName": "Helios 44-2",  // Denormalized for external tools
+      "focalLength": 58,
+      "aperture": "f/2",
+      "shutterSpeed": "1/125"
+      // ... other fields
+    }
+  ]
+}
+```
+
+**Denormalized Lens Name:**
+- Each exposure includes `lensName` for easier external tool usage
+- Python metadata script reads lens name directly from exposure
+- No need to look up lens by ID in external tools
+
+### 7. Python Metadata Script Updates
+
+Updated `apply_filmroll_metadata.py` to support:
+- EI override (uses EI if set, falls back to film ISO)
+- Lens name from exposure data
+- Per-exposure focal length
+- All data properly written to TIF file EXIF tags
+
+### 8. Storage Updates
+
+**IndexedDB:**
+- Added `lenses` object store
+- Migration support for new lens-related fields
+- Proper serialization/deserialization of lens data
+
+**Storage API:**
+- `saveLens(lens: Lens): Promise<void>`
+- `getLenses(): Promise<Lens[]>`
+- `deleteLens(id: string): Promise<void>`
+
+### 9. UI/UX Improvements
+
+**Three-Tab Navigation:**
+- Film Rolls (existing)
+- Cameras (existing)
+- **Lenses (new)** - Flat top-level navigation
+
+**Material-UI Alerts:**
+- Replaced all `alert()` calls with inline MUI Alert components
+- Better UX with dismissible error messages
+- Consistent styling with app theme
+
+**Settings Dialog Enhancement:**
+- Lens selector dropdown
+- EI/Exposure Index selector
+- Focal length slider with lens-aware behavior
+- All settings in one place
+
+## Testing
+
+### E2E Test Coverage
+
+**New Test Suite:**
+- `e2e/lens-management.spec.ts` - 62 new lines
+- Lens CRUD operations
+- Prime vs zoom lens validation
+- Aperture filtering
+- Mid-roll lens changes
+
+**Updated Test Suites:**
+- `e2e/app-navigation.spec.ts` - Added lens tab navigation
+- `e2e/photography-workflow.spec.ts` - Lens integration tests
+- `e2e/utils/page-objects.ts` - Lens management page objects
+- `e2e/utils/test-data.ts` - Test lens data
+
+**CI Integration:**
+- E2E tests run on push to main
+- Tests across 5 browsers (Chromium, Firefox, WebKit, Mobile Chrome, Mobile Safari)
+
+## Technical Details
+
+### Files Changed (27 files)
+- **Added:** 3 new files (~750 lines)
+  - `src/components/LensManagementScreen.tsx`
+  - `src/components/FocalLengthSlider.tsx`
+  - `e2e/lens-management.spec.ts`
+
+- **Modified:** 24 files (~1,300 lines added, ~230 removed)
+  - Core: App.tsx, types.ts, storage layers
+  - Screens: CameraScreen, DetailsScreen, SetupScreen, GalleryScreen, MainScreen
+  - Utils: exportImport, indexedDBStorage
+  - Tests: Multiple E2E test files
+
+### Net Impact
+- **+2,005 lines added**
+- **-232 lines removed**
+- **Net: +1,773 lines**
+
+## User Benefits
+
+1. **Professional Lens Library:** Track all lenses in one place
+2. **Accurate Metadata:** Focal length and lens info in every exposure
+3. **Smart Constraints:** UI prevents invalid settings (e.g., f/1.4 on f/2.8 lens)
+4. **Flexible Workflows:** Change lenses mid-roll, override ISO with EI
+5. **Export-Ready:** All metadata properly formatted for EXIF tools
+6. **Better UX:** Inline errors, adaptive controls, cleaner interface
+
+## Migration Notes
+
+- **Backward Compatible:** Existing exposures without lens data work fine
+- **Automatic Migration:** IndexedDB migration handles schema updates
+- **Export Version:** New exports use v2.0.0 format, old format still importable
+
+## Future Enhancements (Potential)
+
+- [ ] Lens image/photo upload
+- [ ] Lens rental tracking (date ranges)
+- [ ] Lens maintenance notes
+- [ ] Filter exposures by lens
+- [ ] Lens usage statistics
+- [ ] Import lens library from external sources
+
+## Related Documentation
+
+- See `CLAUDE.md` for updated project architecture
+- See `apply_filmroll_metadata.py` docstrings for EXIF details
+- See E2E tests for usage examples
+
+## Commits
+
+```
+e5dbab3 refactor: extract focal legth slider to a component
+f20a6e1 fix: fix slider
+ff17643 fix: fix focal legth locked to available values
+015dfb1 ci: add e2e tests to ci
+8243421 test: fix e2e tests
+4e9287c test: fix e2e tests
+2155c02 feat: add lenses, add EI, add focal length
+```