OM-3vs A7S II
OM System
OM-3 (2024)
Starting from £999 new
Best for Travel, outdoor & adventure photography
View OM-3
VS
Sony
A7S II (2015)
Starting from £799 new
Best for Low-light video, documentary & available-light filmmaking
View A7S II
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.
Low-Light Video, Documentary & Available-Light Filmmaking — A7S II (2015): A landmark in mirrorless history — the first Sony with IBIS and internal 4K, its low-light video capability still impresses today at a used-market price.
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 II (2015)
- Filmmakers and videographers who want legendary low-light performance at a used-price discount
- Documentary shooters working in unpredictable available light conditions
- A7S III shooters who want a second Sony FE body for backup or B-camera use
- Budget-conscious video producers who want full-frame 4K with S-Log at an accessible price
Quick take: The om-3 has the highest resolution at 20mp; the a7s ii is the most affordable. Scroll down for the full spec breakdown.
Full specifications
| Specification | OM-3 (2024) | A7S II (2015) |
|---|---|---|
| Price | £999 | £799 |
| Sensor | 20.4MP Live MOS Micro Four Thirds | 12.1MP full-frame BSI Exmor CMOS |
| Resolution | 20.4MP | 12.1MP |
| Video | 4K/60p (10-bit), C4K/30p, 1080p/120p | 4K/30p internal (full sensor readout), 1080p/120p, S-Log2/S-Log3 |
| Autofocus | Phase-detect AF — subject recognition (human, animal, bird, vehicle) | 169 phase-detect + 25 contrast AF — limited by modern standards |
| Stabilisation | IBIS — up to 6.5 stops (7.5 stops with Sync IS lenses) | 5-axis IBIS — 4.5 stops (first Sony mirrorless with IBIS) |
| Burst Rate | 10fps mechanical, 30fps electronic with AF | 5fps continuous |
| Battery Life | ~400 shots (CIPA) | ~370 shots (CIPA) |
| Weight | 414g (with battery) | 584g body only |
| Dimensions | 122.3 × 84.6 × 49.4mm | 126.9 × 95.7 × 60.3mm |
| Weather Sealed | Yes | Yes |
| Viewfinder | EVF, 2.36M dots, 0.74× magnification | EVF, 2.36M dots, 0.71× magnification |
| Screen | 3.0" fully articulating touchscreen | 3.0" tilting LCD, 1.23M dots |
| Mount | Micro Four Thirds | Sony FE mount (full-frame E-mount) |
| Memory Cards | Single SD UHS-II slot | Dual SD UHS-I slots |
| Connectivity | USB-C, Wi-Fi, Bluetooth | USB Micro-B, Bluetooth (via app), Wi-Fi, 3.5mm mic jack |
Suitability by genre
| Genre | OM-3 | A7S II |
|---|---|---|
| Travel | — | |
| Wildlife | — | |
| Landscape | — | |
| Street | ||
| Portrait | ||
| Vlogging & Video | ||
| Low Light | — | |
| Wedding | — | |
| Sports | — |
More comparisons with OM-3
Camera family history