EOS RPvs Pentax K-3 Mark IIIvs Sigma fp
Pentax
Pentax K-3 Mark III (2021)
From £1699
Best for DSLR enthusiasts & outdoor photographers
View Pentax K-3 Mark III
Sigma
Sigma fp (2019)
From £1499
Best for Creative filmmakers & experimental photographers
View Sigma fp
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.
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.
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
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
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) | Sigma fp (2019) |
|---|---|---|---|
| Price | £799 | £1,699 | £1,499 |
| Sensor | 26.2MP Full-Frame CMOS | 25.7MP APS-C BSI CMOS (AA-filterless) | 24.6MP full-frame Bayer CMOS |
| Resolution | 26.2MP | 25.7MP | 24.6MP |
| Video | 4K/24p (with 1.7× crop), 1080p/60p | 4K/30p, 1080p/60p | 12-bit Cinema DNG RAW, 4K/24p, 1080p/120p |
| Autofocus | Dual Pixel CMOS AF, 4779 manually selectable positions | SAFOX 13 phase-detect, 101-point (25 cross-type) | Contrast-detect AF with face/eye detection |
| Stabilisation | None (no IBIS) | 5.5-stop 5-axis IBIS (Shake Reduction III) | None (lens-based only) |
| Burst Rate | 5fps mechanical | 12fps | 18fps electronic |
| Battery Life | ~250 shots (CIPA) — very limited | 800 shots (CIPA) | 200 shots (CIPA) |
| Weight | 485g (body, battery, card) | 820g body only | 422g body only |
| Dimensions | 132.5 × 85.0 × 70.0mm | 134.5 × 103.5 × 73.5mm | 112.6 × 69.9 × 45.3mm |
| Weather Sealed | No | Yes | No |
| Viewfinder | EVF, 2.36M dots, 0.70× magnification | Optical pentaprism, 100% coverage, 1.05× magnification | None |
| Screen | 3.0" vari-angle touchscreen, 1.04M dots | 3.2" tilting touchscreen | 3.15" fixed touchscreen |
| Mount | Canon RF-mount | Pentax KF-mount | Leica L-mount |
| Memory Cards | Single SD UHS-II | Dual SD UHS-II | Single SD UHS-II + CFexpress Type B (via adapter) |
| Connectivity | USB-C, Wi-Fi, Bluetooth | USB-C, Wi-Fi, Bluetooth | USB-C 3.1, Wi-Fi, Bluetooth |
Compare pairs from this group