OM-3vs A7S III
OM System
OM-3 (2024)
Starting from £999 new
Best for Travel, outdoor & adventure photography
View OM-3
Sony
A7S III (2020)
Starting from £2999 new
Best for Professional video & low-light filmmaking
View A7S 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.
Professional Video & Low-Light Filmmaking — A7S III (2020): If video is your primary discipline, the A7S III is the camera. 4K/120p at 10-bit in a weather-sealed body with a 9.44M dot EVF is an extraordinary package. The 12MP sensor isn't limiting for video — and it's usable at ISO 409,600 in a pinch.
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
A7S III (2020)
- Filmmakers and videographers who need 4K/120p at 10-bit
- Event videographers who shoot in dark venues regularly
- Documentary filmmakers who need reliable AF and weather sealing
- Hybrid shooters where video is primary and stills are secondary
Quick take: The om-3 has the highest resolution at 20mp; the om-3 is the most affordable. Scroll down for the full spec breakdown.
Full specifications
| Specification | OM-3 (2024) | A7S III (2020) |
|---|---|---|
| Price | £999 | £2,999 |
| Sensor | 20.4MP Live MOS Micro Four Thirds | 12.1MP Full-Frame BSI CMOS (12-bit, back-illuminated) |
| Resolution | 20.4MP | 12.1MP |
| Video | 4K/60p (10-bit), C4K/30p, 1080p/120p | 4K/120p 10-bit, 4K/60p 10-bit S-Cinetone/S-Log3, 1080p/240p |
| Autofocus | Phase-detect AF — subject recognition (human, animal, bird, vehicle) | Phase-detect, 759 points, real-time Eye AF (human & animal), subject recognition |
| Stabilisation | IBIS — up to 6.5 stops (7.5 stops with Sync IS lenses) | 5.5-stop IBIS |
| Burst Rate | 10fps mechanical, 30fps electronic with AF | 10fps mechanical |
| Battery Life | ~400 shots (CIPA) | ~600 shots (CIPA) / ~70min continuous 4K recording |
| Weight | 414g (with battery) | 699g (body, battery, card) |
| Dimensions | 122.3 × 84.6 × 49.4mm | 128.9 × 96.9 × 80.8mm |
| Weather Sealed | Yes | Yes |
| Viewfinder | EVF, 2.36M dots, 0.74× magnification | OLED EVF, 9.44M dots, 0.90× magnification — best EVF Sony has made |
| Screen | 3.0" fully articulating touchscreen | 3.0" vari-angle touchscreen, 1.44M dots |
| Mount | Micro Four Thirds | Sony E-mount |
| Memory Cards | Single SD UHS-II slot | Dual CFexpress Type A / SD UHS-II (both slots) |
| Connectivity | USB-C, Wi-Fi, Bluetooth | USB-C (USB 3.2 Gen 2), full-size HDMI, Wi-Fi 6, Bluetooth |
Suitability by genre
| Genre | OM-3 | A7S III |
|---|---|---|
| Travel | ||
| Wildlife | ||
| Landscape | — | |
| Street | ||
| Portrait | ||
| Vlogging & Video | — | |
| Video | — |
More comparisons with OM-3
Camera family history