OM-3vs A7R III
OM System
OM-3 (2024)
Starting from £999 new
Best for Travel, outdoor & adventure photography
View OM-3
VS
Sony
A7R III (2017)
Starting from £1799 new
Best for Landscape, studio & commercial photography
View A7R III
GearScore™ Verdict — Which should you buy?
Travel, Outdoor & Adventure Photography — OM-3 (2024): The ideal mid-range OM System camera — weather sealed, class-leading IBIS, and superb computational features in a compact body.
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-3 (2024)
- Outdoor and adventure photographers who need weather sealing and compact size
- Wildlife and bird photographers wanting improved AF over the OM-5
- Travel shooters who want a rugged, lightweight MFT system
- OM-5 or E-M5 III owners wanting better autofocus without going to the OM-1
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 om-3 is the most affordable. Scroll down for the full spec breakdown.
Full specifications
| Specification | OM-3 (2024) | A7R III (2017) |
|---|---|---|
| Price | £999 | £1,799 |
| Sensor | 20.4MP Live MOS Micro Four Thirds | 42.4MP full-frame BSI Exmor R CMOS |
| Resolution | 20.4MP | 42.4MP |
| Video | 4K/60p (10-bit), C4K/30p, 1080p/120p | 4K/30p (full-frame readout), 1080p/120p |
| Autofocus | Phase-detect AF — subject recognition (human, animal, bird, vehicle) | 399 phase-detect + 425 contrast AF points — real-time Eye AF |
| Stabilisation | IBIS — up to 6.5 stops (7.5 stops with Sync IS lenses) | 5-axis IBIS — 5.5 stops |
| Burst Rate | 10fps mechanical, 30fps electronic with AF | 10fps with AF/AE tracking |
| Battery Life | ~400 shots (CIPA) | ~650 shots (CIPA) |
| Weight | 414g (with battery) | 650g body only |
| Dimensions | 122.3 × 84.6 × 49.4mm | 126.9 × 95.6 × 73.7mm |
| Weather Sealed | Yes | Yes |
| Viewfinder | EVF, 2.36M dots, 0.74× magnification | 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 | Single SD UHS-II slot | 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-3 | A7R III |
|---|---|---|
| Travel | — | |
| Wildlife | — | |
| Landscape | ||
| Street | ||
| Portrait | ||
| Vlogging & Video | ||
| Wedding | — | |
| Sports | — |
More comparisons with OM-3
Camera family history