Pentax K-3 Mark IIIvs FX3
Pentax
Pentax K-3 Mark III (2021)
Starting from £1699 new
Best for DSLR enthusiasts & outdoor photographers
View Pentax K-3 Mark III
Sony
FX3 (2021)
Starting from £3799 new
Best for Professional video, documentary & cinematic filmmaking
View FX3
GearScore™ Verdict — Which should you buy?
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.
Professional Video, Documentary & Cinematic Filmmaking — FX3 (2021): The definitive run-and-gun cinema camera — A7S III sensor quality in a body built specifically for video professionals.
Who should buy what
Pentax K-3 Mark III (2021)
- DSLR photographers who want the finest APS-C optical viewfinder experience
- Outdoor and weather photographers who need robust all-weather sealing
- Pentax lens owners who want to use their existing K-mount glass
- Photographers who prefer optical viewfinders and refuse to switch to mirrorless
FX3 (2021)
- Professional videographers and filmmakers who need cinema-quality colour science in a compact body
- Documentary and run-and-gun shooters who need 4K/120p and built-in XLR audio
- Sony A7S III owners who want a purpose-built video body alongside their stills camera
- Gimbal and drone operators who need a compact full-frame cinema camera
Quick take: The pentax k-3 mark iii has the highest resolution at 26mp; the pentax k-3 mark iii is the most affordable. Scroll down for the full spec breakdown.
Full specifications
| Specification | Pentax K-3 Mark III (2021) | FX3 (2021) |
|---|---|---|
| Price | £1,699 | £3,799 |
| Sensor | 25.7MP APS-C BSI CMOS (AA-filterless) | 12.1MP full-frame BSI Exmor R CMOS (same as A7S III) |
| Resolution | 25.7MP | 12.1MP |
| Video | 4K/30p, 1080p/60p | 4K/120p, 4K/60p 10-bit, 12-bit RAW output, S-Log3, S-Cinetone |
| Autofocus | SAFOX 13 phase-detect, 101-point (25 cross-type) | Real-time tracking with subject recognition (human, animal) |
| Stabilisation | 5.5-stop 5-axis IBIS (Shake Reduction III) | 5-axis IBIS — 5 stops |
| Burst Rate | 12fps | 10fps mechanical, 10fps electronic |
| Battery Life | 800 shots (CIPA) | ~640 shots (CIPA) |
| Weight | 820g body only | 715g body only (with XLR handle) |
| Dimensions | 134.5 × 103.5 × 73.5mm | 129.7 × 78.0 × 84.5mm |
| Weather Sealed | Yes | Yes |
| Viewfinder | Optical pentaprism, 100% coverage, 1.05× magnification | None — monitor/external EVF use only |
| Screen | 3.2" tilting touchscreen | 3.0" touchscreen, fully articulating |
| Mount | Pentax KF-mount | Sony FE mount (full-frame E-mount) |
| Memory Cards | Dual SD UHS-II | Dual CFexpress Type A / SD UHS-II slots |
| Connectivity | USB-C, Wi-Fi, Bluetooth | USB-C (10Gbps), full-size HDMI, XLR via handle, Bluetooth, Wi-Fi |
Suitability by genre
| Genre | Pentax K-3 Mark III | FX3 |
|---|---|---|
| Landscape | — | |
| Wildlife | — | |
| Sports & Action | — | |
| Portrait | ||
| Travel | ||
| Vlogging & Video | ||
| Low Light | — | |
| Street | — | |
| Wedding | — |
More comparisons with Pentax K-3 Mark III
Camera family history