EOS RPvs Pentax K-3 Mark IIIvs A6400

GearFrame · Updated March 2026

Canon EOS RP Canon EOS RP (2019) From £799 Best for Entry full-frame stills photography View EOS RP
VS
Pentax Pentax K-3 Mark III Pentax Pentax K-3 Mark III (2021) From £1699 Best for DSLR enthusiasts & outdoor photographers View Pentax K-3 Mark III
VS
Sony A6400 Sony A6400 (2019) From £899 Best for Content creation & vlogging View A6400

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.

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.

↓ Full specifications below

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

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

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 is weather sealed. Scroll down for the full spec breakdown.

Full specifications

Specification EOS RP (2019)Pentax K-3 Mark III (2021)A6400 (2019)
Price £799 £1,699 £899
Sensor 26.2MP Full-Frame CMOS 25.7MP APS-C BSI CMOS (AA-filterless) 24.2MP APS-C Exmor CMOS BSI
Resolution 26.2MP 25.7MP 24.2MP
Video 4K/24p (with 1.7× crop), 1080p/60p 4K/30p, 1080p/60p 4K/30p (6K oversampled, no crop), 1080p/120p slow-motion
Autofocus Dual Pixel CMOS AF, 4779 manually selectable positions SAFOX 13 phase-detect, 101-point (25 cross-type) Phase-detect, 425 points, real-time Eye AF & animal AF
Stabilisation None (no IBIS) 5.5-stop 5-axis IBIS (Shake Reduction III) None (no IBIS)
Burst Rate 5fps mechanical 12fps 11fps mechanical, 8fps with AF tracking
Battery Life ~250 shots (CIPA) — very limited 800 shots (CIPA) ~410 shots (CIPA)
Weight 485g (body, battery, card) 820g body only 403g (body, battery, card)
Dimensions 132.5 × 85.0 × 70.0mm 134.5 × 103.5 × 73.5mm 120.0 × 66.9 × 59.7mm
Weather Sealed No Yes No
Viewfinder EVF, 2.36M dots, 0.70× magnification Optical pentaprism, 100% coverage, 1.05× magnification EVF, 2.36M dots, 0.70× magnification
Screen 3.0" vari-angle touchscreen, 1.04M dots 3.2" tilting touchscreen 3.0" tilting touchscreen, 180° flip for selfie/vlog, 921k dots
Mount Canon RF-mount Pentax KF-mount Sony E-mount
Memory Cards Single SD UHS-II Dual SD UHS-II Single SD UHS-I
Connectivity USB-C, Wi-Fi, Bluetooth USB-C, Wi-Fi, Bluetooth Micro-USB, Wi-Fi, Bluetooth, NFC
⚡ Compare specs side by side EOS RP prices → Pentax K-3 Mark III prices → A6400 prices →

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