Canon EOS R3vs Sigma fpvs A7 III
Canon
Canon EOS R3 (2021)
From £5999
Best for Sports & photojournalism professionals
View Canon EOS R3
Sigma
Sigma fp (2019)
From £1499
Best for Creative filmmakers & experimental photographers
View Sigma fp
Which should you buy?
Sports & Photojournalism Professionals — Canon EOS R3 (2021): The pinnacle of Canon's mirrorless lineup for speed — Eye Control AF and 30fps burst in the most rugged body Canon has ever produced.
Creative Filmmakers & Experimental Photographers — Sigma fp (2019): The smallest full-frame camera in the world — Cinema DNG RAW and L-mount flexibility in a pocket-sized body that rewards creative shooters.
All-Round Photography & Video — A7 III (2018): Still one of the best all-round cameras money can buy — particularly strong used. The A7 III proved that full-frame doesn't have to mean compromises, and nothing at this price point has meaningfully beaten it.
Who should buy what
Canon EOS R3 (2021)
- You shoot sport, motorsport, wildlife, or news at a professional level
- You need Canon's most reliable and fastest autofocus available
- You need extreme weather sealing for demanding shooting conditions
Sigma fp (2019)
- You're a filmmaker building a cinema rig where the smallest full-frame body is essential
- You want L-mount compatibility to pair with Sigma Art or Leica SL lenses
- You prioritise video and cinema colour over stills ergonomics and functionality
A7 III (2018)
- Enthusiast photographers upgrading from APS-C for the first time
- Working photographers who need reliable AF and weather sealing
- Anyone who shoots in low light regularly
- Hybrid shooters needing both stills and video performance
Quick take: The sigma fp has the highest resolution at 25mp; the sigma fp is the most affordable; only the canon eos r3, a7 iii are weather sealed. Scroll down for the full spec breakdown.
Full specifications
| Specification | Canon EOS R3 (2021) | Sigma fp (2019) | A7 III (2018) |
|---|---|---|---|
| Price | £5,999 | £1,499 | £1,699 |
| Sensor | 24.1MP full-frame BSI stacked CMOS | 24.6MP full-frame Bayer CMOS | 24.2MP Full-Frame Exmor R BSI CMOS |
| Resolution | 24.1MP | 24.6MP | 24.2MP |
| Video | 6K RAW, 4K/120p, 1080p/180p | 12-bit Cinema DNG RAW, 4K/24p, 1080p/120p | 4K/30p (6K oversampled), 1080p/120p slow-motion |
| Autofocus | Dual Pixel CMOS AF II with Eye Control AF | Contrast-detect AF with face/eye detection | Phase-detect, 693 points, real-time Eye AF & animal AF |
| Stabilisation | 8-stop IBIS | None (lens-based only) | 5-axis IBIS, 5 stops |
| Burst Rate | 30fps electronic / 12fps mechanical | 18fps electronic | 10fps with AF/AE tracking |
| Battery Life | 620 shots (CIPA) | 200 shots (CIPA) | ~710 shots (CIPA) |
| Weight | 1015g body only | 422g body only | 565g (body, battery, card) |
| Dimensions | 150.0 × 142.6 × 87.2mm | 112.6 × 69.9 × 45.3mm | 126.9 × 95.6 × 73.7mm |
| Weather Sealed | Yes | No | Yes |
| Viewfinder | 0.76" OLED EVF, 5.76M dots, 120fps | None | EVF, 2.36M dots, 0.78× magnification |
| Screen | 3.2" fully articulating touchscreen | 3.15" fixed touchscreen | 3.0" tilting touchscreen, 921k dots |
| Mount | Canon RF | Leica L-mount | Sony E-mount |
| Memory Cards | Dual CFexpress Type B | Single SD UHS-II + CFexpress Type B (via adapter) | Dual SD (UHS-II slot 1, UHS-I slot 2) |
| Connectivity | USB-C 3.2, HDMI full-size, Wi-Fi 6, Bluetooth, LAN | USB-C 3.1, Wi-Fi, Bluetooth | USB-C (USB 3.2), Wi-Fi, Bluetooth, NFC |
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