A6400vs A7S III
Which should you buy?
Content Creation & Vlogging — A6400 (2019): The best value APS-C Sony you can buy — especially used. Real-time Eye AF at this price point was transformative when it launched and still makes it one of the most reliable autofocus systems in the lineup.
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
A6400 (2019)
- Vloggers and content creators who need a flip screen and reliable AF
- Photographers upgrading from a compact or smartphone
- Beginners who want room to grow into a full E-mount lens ecosystem
- Anyone prioritising autofocus performance at an accessible price
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 a6400 has the highest resolution at 24mp; the a6400 is the most affordable; only the a7s iii is weather sealed. Scroll down for the full spec breakdown.
Full specifications
| Specification | A6400 (2019) | A7S III (2020) |
|---|---|---|
| Price | £899 | £2,999 |
| Sensor | 24.2MP APS-C Exmor CMOS BSI | 12.1MP Full-Frame BSI CMOS (12-bit, back-illuminated) |
| Resolution | 24.2MP | 12.1MP |
| Video | 4K/30p (6K oversampled, no crop), 1080p/120p slow-motion | 4K/120p 10-bit, 4K/60p 10-bit S-Cinetone/S-Log3, 1080p/240p |
| Autofocus | Phase-detect, 425 points, real-time Eye AF & animal AF | Phase-detect, 759 points, real-time Eye AF (human & animal), subject recognition |
| Stabilisation | None (no IBIS) | 5.5-stop IBIS |
| Burst Rate | 11fps mechanical, 8fps with AF tracking | 10fps mechanical |
| Battery Life | ~410 shots (CIPA) | ~600 shots (CIPA) / ~70min continuous 4K recording |
| Weight | 403g (body, battery, card) | 699g (body, battery, card) |
| Dimensions | 120.0 × 66.9 × 59.7mm | 128.9 × 96.9 × 80.8mm |
| Weather Sealed | No | Yes |
| Viewfinder | EVF, 2.36M dots, 0.70× magnification | OLED EVF, 9.44M dots, 0.90× magnification — best EVF Sony has made |
| Screen | 3.0" tilting touchscreen, 180° flip for selfie/vlog, 921k dots | 3.0" vari-angle touchscreen, 1.44M dots |
| Mount | Sony E-mount | Sony E-mount |
| Memory Cards | Single SD UHS-I | Dual CFexpress Type A / SD UHS-II (both slots) |
| Connectivity | Micro-USB, Wi-Fi, Bluetooth, NFC | USB-C (USB 3.2 Gen 2), full-size HDMI, Wi-Fi 6, Bluetooth |
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