EOS RPvs Pentax K-3 Mark IIIvs Sony A9 III
Pentax
Pentax K-3 Mark III (2021)
From £1699
Best for DSLR enthusiasts & outdoor photographers
View Pentax K-3 Mark III
Which should you buy?
Entry Full-Frame Stills Photography — EOS RP (2019): An affordable gateway into the RF system. The RP makes sense as a stepping stone camera — if you're committed to Canon RF glass, this is the cheapest full-frame body to buy those lenses for. Just manage expectations on video and battery life.
Dslr Enthusiasts & Outdoor Photographers — Pentax K-3 Mark III (2021): The finest APS-C DSLR ever made — class-leading weather sealing, optical viewfinder, 5-axis IBIS, and extraordinary build for photographers committed to DSLR.
Sports & Action Professionals — Sony A9 III (2023): A paradigm-shifting camera — the global shutter eliminates every rolling shutter limitation that has constrained action photography for years.
Who should buy what
EOS RP (2019)
- Canon users who want to start investing in RF glass affordably
- Stills photographers who shoot primarily in good light
- Anyone coming from a Canon DSLR wanting the RF system at low cost
- Travel photographers who prioritise compactness over video specs
Pentax K-3 Mark III (2021)
- You're a committed DSLR photographer with significant investment in Pentax glass
- You shoot in extreme weather conditions and place build quality and reliability above everything
- You prefer optical viewfinder performance and want the best modern APS-C DSLR available
Sony A9 III (2023)
- You shoot professional sport, motorsport, or action and need zero rolling shutter distortion
- You need reliable high-speed flash sync for studio or on-location action work
- You want the absolute pinnacle of Sony's action and sports camera technology
Quick take: The eos rp has the highest resolution at 26mp; the eos rp is the most affordable; only the pentax k-3 mark iii, sony a9 iii are weather sealed. Scroll down for the full spec breakdown.
Full specifications
| Specification | EOS RP (2019) | Pentax K-3 Mark III (2021) | Sony A9 III (2023) |
|---|---|---|---|
| Price | £799 | £1,699 | £5,999 |
| Sensor | 26.2MP Full-Frame CMOS | 25.7MP APS-C BSI CMOS (AA-filterless) | 24.6MP full-frame Exmor RS CMOS (global shutter) |
| Resolution | 26.2MP | 25.7MP | 24.6MP |
| Video | 4K/24p (with 1.7× crop), 1080p/60p | 4K/30p, 1080p/60p | 4K/120p, 4K/60p, 1080p/240p |
| Autofocus | Dual Pixel CMOS AF, 4779 manually selectable positions | SAFOX 13 phase-detect, 101-point (25 cross-type) | AI subject recognition AF, 759-point phase-detect |
| Stabilisation | None (no IBIS) | 5.5-stop 5-axis IBIS (Shake Reduction III) | 8-stop IBIS |
| Burst Rate | 5fps mechanical | 12fps | 120fps blackout-free electronic |
| Battery Life | ~250 shots (CIPA) — very limited | 800 shots (CIPA) | 530 shots (CIPA) |
| Weight | 485g (body, battery, card) | 820g body only | 703g body only |
| Dimensions | 132.5 × 85.0 × 70.0mm | 134.5 × 103.5 × 73.5mm | 136.1 × 96.9 × 82.9mm |
| Weather Sealed | No | Yes | Yes |
| Viewfinder | EVF, 2.36M dots, 0.70× magnification | Optical pentaprism, 100% coverage, 1.05× magnification | 0.64" Quad-XGA OLED EVF, 9.44M dots |
| Screen | 3.0" vari-angle touchscreen, 1.04M dots | 3.2" tilting touchscreen | 3.2" fully articulating touchscreen |
| Mount | Canon RF-mount | Pentax KF-mount | Sony FE (E-mount) |
| Memory Cards | Single SD UHS-II | Dual SD UHS-II | Dual CFexpress Type A / SD UHS-II |
| Connectivity | USB-C, Wi-Fi, Bluetooth | USB-C, Wi-Fi, Bluetooth | USB-C 3.2, HDMI A, Wi-Fi 6, Bluetooth 5.3 |
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