Pentax
Pentax K-3 Mark III 2021
Best for DSLR enthusiasts & outdoor photographers
£1699
list price · used from £856 at eBay
Decision tools · Compare
Pentax K-3 Mark III vs A6400
Quick take: The Pentax K-3 Mark III has the highest resolution at 26MP; the A6400 is the most affordable.
16 specs side by side·15 genres scored·UK prices from Wex Photo Video and Clifton Cameras
How to read this page. Highlighted cells win that row on the spec alone. Genre scores are the engine's base scores (enthusiast, photo and video); Camera Match re-weights them for your level and priorities. Price buttons are affiliate links; the price you pay is the same.
Price buttons are affiliate links — GearFrame may earn a commission at no extra cost to you. It never affects a score. Learn more
Verdictwhich should you buy?
Pentax K-3 Mark III — Dslr Enthusiasts & Outdoor Photographers: The finest APS-C DSLR ever made — class-leading weather sealing, optical viewfinder, 5-axis IBIS, and extraordinary build for photographers committed to DSLR.
A6400 — Content Creation & Vlogging: 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.
Who should buy what
Pentax K-3 Mark III (2021)
is the right camera for you if…
- 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
A6400 (2019)
is the right camera for you if…
- 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
Full specificationsthe better value in each row is highlighted
| Specification | Pentax K-3 Mark IIIPentax · 2021 | A6400Sony · 2019 |
|---|---|---|
| Price | £1,699 | £749Best |
| Sensor | 25.7MP APS-C BSI CMOS (AA-filterless) | 24.2MP APS-C Exmor CMOS BSI |
| Resolution | 25.7MPBest | 24.2MP |
| Video | 4K/30p, 1080p/60p | 4K/30p (6K oversampled, no crop), 1080p/120p slow-motion |
| Autofocus | SAFOX 13 phase-detect, 101-point (25 cross-type) | Phase-detect, 425 points, real-time Eye AF & animal AF |
| Stabilisation | 5.5-stop 5-axis IBIS (Shake Reduction III) | No stabilisation |
| Burst Rate | 12fpsBest | 11fps mechanical, 8fps with AF tracking |
| Battery Life | 800 shots (CIPA)Best | ~410 shots (CIPA) |
| Weight | 820g (body only) | 403g (with battery and card)Best |
| Dimensions | 134.5 × 103.5 × 73.5mm | 120.0 × 66.9 × 59.7mm |
| Weather Sealed | Yes | Yes |
| Viewfinder | Optical pentaprism, 100% coverage, 1.05× magnification | EVF, 2.36M dots, 0.70× magnification |
| Screen | 3.2" fixed touchscreen | 3.0" tilting touchscreen, 180° flip for selfie/vlog, 921k dots |
| Mount | Pentax KF-mount | Sony E-mount |
| Memory Cards | Dual SD UHS-II | Single SD UHS-I |
| Connectivity | USB-C, Wi-Fi, Bluetooth | Micro-USB, Wi-Fi, Bluetooth, NFC |
Wins the row — price, resolution, burst, battery, weight and sealing are compared; text specs aren't ranked.
How they score by genreengine base scores out of 10
Genre
Pentax K-3 Mark III
A6400
Portrait
6.6/10
6.7/10
Street
5.2/10
7.3/10
Travel
5.5/10
6.9/10
Wedding & Events
7.0/10
5.6/10
Filmmaking
5.4/10
5.1/10
Documentary
6.4/10
6.1/10
Sports & Action
6.8/10
6.9/10
Landscape
6.2/10
5.6/10
Wildlife
6.8/10
7.4/10
Casual
4.3/10
5.8/10
Food
5.4/10
6.1/10
Macro
4.9/10
5.2/10
Architecture
6.0/10
5.5/10
Astrophotography
6.5/10
6.0/10
Vlogging & Video
—
6.0/10
Scores come from the same engine as Camera Match: verified specifications weighted by what each genre needs, with documented adjustments. The product page and this table show the enthusiast base score. See how scores are calculated →
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