Upgrade Guide
Sony FX3→Sony Sony RX1R III
Is it worth upgrading? Spec analysis, key improvements, and our verdict.
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Worthwhile
Clear improvements over the FX3. Whether it justifies the cost depends on which upgrades matter most to your shooting.
What's new in the Sony RX1R III
-
Resolution61MP vs 12MP (+49MP)
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Generation4 years newer (2025 vs 2021)
Unchanged or similar
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Weather sealingNot present in new body
Suitability by genre
Base scores — computed from verified specs for an enthusiast shooting photo and video. The Upgrade Checker adjusts them for your skill level.
| Genre | FX3 | Sony RX1R III | |
|---|---|---|---|
| Portrait | +0.2 | ||
| Street | +3.3 | ||
| Travel | +0.5 | ||
| Wedding & Events | -0.3 | ||
| Vlogging & Video | — | ||
| Filmmaking | -3.8 | ||
| Documentary | -2.5 | ||
| Sports & Action | — | ||
| Landscape | +1.0 | ||
| Wildlife | — | ||
| Casual | -0.2 | ||
| Food | -0.4 | ||
| Macro | -0.7 | ||
| Architecture | +0.8 | ||
| Astrophotography | -0.5 |
Full spec comparison
| Spec | FX3 | Sony RX1R III | |
|---|---|---|---|
| Price | £3,799 | £3,899 | |
| Released | 2021 | 2025 | ↑ |
| Sensor | 12.1MP full-frame BSI Exmor R CMOS (same as A7S III) | 61MP full-frame Exmor R BSI CMOS | |
| Resolution | 12MP | 61MP | ↑ |
| Video | 4K/120p, 4K/60p 10-bit, 12-bit RAW output, S-Log3, S-Cinetone | 4K/30p, 10-bit | |
| Autofocus | Real-time tracking with subject recognition (human, animal) | Hybrid phase-detect AF (693 points) with eye detection | |
| Stabilisation | 5-axis IBIS — 5 stops | No stabilisation | |
| Burst Rate | 10fps mechanical, 10fps electronic | 5fps | ↓ |
| Battery Life | ~640 shots (CIPA) | 300 shots (CIPA, LCD) | ↓ |
| Weight | 715g (body only) | 496g (with battery and card) | ↑ |
| Weather Sealed | Yes | Not weather sealed | ↓ |
| Viewfinder | None — monitor/external EVF use only | EVF, 2.36M dots | |
| Screen | 3.0" touchscreen, fully articulating | Tilting touchscreen | |
| Mount | Sony FE mount (full-frame E-mount) | Fixed 35mm f/2 Zeiss Sonnar lens | |
| Memory Cards | Dual CFexpress Type A / SD UHS-II slots | Single SD (UHS-II) |
Compare side-by-side
⚖️ Compare these cameras
See FX3 and Sony RX1R III next to each other with our interactive comparison tool.
Get a personalised upgrade score
Run the upgrade checker →
Tell us what you shoot and we'll score the Sony RX1R III against your specific genres — not just specs.
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