OM System OM-1 Mark IIvs A7S II
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
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?
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.
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 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
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 system om-1 mark ii has the highest resolution at 20mp; the a7s ii is the most affordable. Scroll down for the full spec breakdown.
Full specifications
| Specification | OM System OM-1 Mark II (2024) | A7S II (2015) |
|---|---|---|
| Price | £1,999 | £799 |
| Sensor | 20MP Micro Four Thirds Live MOS | 12.1MP full-frame BSI Exmor CMOS |
| Resolution | 20.0MP | 12.1MP |
| Video | 4K/60p, 1080p/240p, 4K HLG | 4K/30p internal (full sensor readout), 1080p/120p, S-Log2/S-Log3 |
| Autofocus | AI subject detection AF (birds, animals, motorsport) | 169 phase-detect + 25 contrast AF — limited by modern standards |
| Stabilisation | 8.5-stop IBIS | 5-axis IBIS — 4.5 stops (first Sony mirrorless with IBIS) |
| Burst Rate | 120fps with AF tracking | 5fps continuous |
| Battery Life | 520 shots (CIPA) | ~370 shots (CIPA) |
| Weight | 599g body only | 584g body only |
| Dimensions | 134.8 × 91.6 × 72.7mm | 126.9 × 95.7 × 60.3mm |
| Weather Sealed | Yes | Yes |
| Viewfinder | 0.83" OLED EVF, 5.76M dots, 120fps | 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 | Dual SD UHS-II | 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 System OM-1 Mark II | A7S II |
|---|---|---|
| Wildlife | — | |
| Sports & Action | — | |
| Landscape | — | |
| Travel | — | |
| Portrait | ||
| Vlogging & Video | ||
| Low Light | — | |
| Wedding | — | |
| Street | — | |
| Sports | — |
More comparisons with OM System OM-1 Mark II
Camera family history