OM System OM-1 Mark IIvs A7R III
OM System
OM System OM-1 Mark II (2024)
Starting from £1999 new
Best for Wildlife, birds & outdoor sports
View OM System OM-1 Mark II
Sony
A7R III (2017)
Starting from £1799 new
Best for Landscape, studio & commercial photography
View A7R III
GearScore™ Verdict — Which should you buy?
Wildlife, Birds & Outdoor Sports — OM System OM-1 Mark II (2024): OM System's most capable camera — 120fps AF burst, AI subject detection, and IP53 weather sealing make it the best-value pro wildlife camera.
Landscape, Studio & Commercial Photography — A7R III (2017): The camera that converted professionals to mirrorless — 42MP, IBIS, and 10fps in a body that still competes today.
Who should buy what
OM System OM-1 Mark II (2024)
- Wildlife and bird photographers who need the best subject tracking in MFT
- Sports photographers who want weather sealing and 50fps burst
- OM-1 owners looking for a meaningful autofocus upgrade
- Professionals who need pro-grade weather sealing in the lightest possible system
A7R III (2017)
- Landscape and studio photographers who need 42MP resolution at a used-price discount vs A7R IV
- Canon/Nikon DSLR professionals considering a mirrorless switch at a lower investment
- Commercial and product photographers who want full-frame resolution with IBIS for handheld work
- Portrait photographers who want the sharpest possible full-frame files for large print work
Quick take: The a7r iii has the highest resolution at 42mp; the a7r iii is the most affordable. Scroll down for the full spec breakdown.
Full specifications
| Specification | OM System OM-1 Mark II (2024) | A7R III (2017) |
|---|---|---|
| Price | £1,999 | £1,799 |
| Sensor | 20MP Micro Four Thirds Live MOS | 42.4MP full-frame BSI Exmor R CMOS |
| Resolution | 20.0MP | 42.4MP |
| Video | 4K/60p, 1080p/240p, 4K HLG | 4K/30p (full-frame readout), 1080p/120p |
| Autofocus | AI subject detection AF (birds, animals, motorsport) | 399 phase-detect + 425 contrast AF points — real-time Eye AF |
| Stabilisation | 8.5-stop IBIS | 5-axis IBIS — 5.5 stops |
| Burst Rate | 120fps with AF tracking | 10fps with AF/AE tracking |
| Battery Life | 520 shots (CIPA) | ~650 shots (CIPA) |
| Weight | 599g body only | 650g body only |
| Dimensions | 134.8 × 91.6 × 72.7mm | 126.9 × 95.6 × 73.7mm |
| Weather Sealed | Yes | Yes |
| Viewfinder | 0.83" OLED EVF, 5.76M dots, 120fps | EVF, 3.69M dots, 0.78× magnification |
| Screen | 3.0" fully articulating touchscreen | 3.0" touchscreen, tilting |
| Mount | Micro Four Thirds | Sony FE mount (full-frame E-mount) |
| Memory Cards | Dual SD UHS-II | Dual SD slots (one UHS-II) |
| Connectivity | USB-C, Wi-Fi, Bluetooth | USB-C, Bluetooth, Wi-Fi, 3.5mm mic jack |
Suitability by genre
| Genre | OM System OM-1 Mark II | A7R III |
|---|---|---|
| Wildlife | — | |
| Sports & Action | — | |
| Landscape | ||
| Travel | — | |
| Portrait | ||
| Vlogging & Video | ||
| Wedding | — | |
| Street | — | |
| Sports | — |
More comparisons with OM System OM-1 Mark II
Camera family history