Upgrade Guide
Pentax K-S1→Pentax Pentax K-3 Mark III
Is it worth upgrading? Spec analysis, key improvements, and our verdict.
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Worthwhile
Clear improvements over the K-S1. Whether it justifies the cost depends on which upgrades matter most to your shooting.
What's new in the Pentax K-3 Mark III
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Resolution26MP vs 20MP (+6MP)
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Weather sealingAdded — fully sealed body
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StabilisationIBIS added — significant for handheld and video
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Burst rate12fps vs 5.4fps
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Battery life800 shots (CIPA) vs ~410 shots (CIPA)
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Generation7 years newer (2021 vs 2014)
Suitability by genre
Base scores — computed from verified specs for an enthusiast shooting photo and video. The Upgrade Checker adjusts them for your skill level.
| Genre | K-S1 | Pentax K-3 Mark III | |
|---|---|---|---|
| Portrait | +0.9 | ||
| Street | -0.3 | ||
| Travel | +0.4 | ||
| Wedding & Events | +2.8 | ||
| Documentary | +2.7 | ||
| Sports & Action | +2.0 | ||
| Landscape | +2.0 | ||
| Wildlife | +1.4 | ||
| Casual | +0.6 | ||
| Food | +0.8 | ||
| Macro | +0.5 | ||
| Architecture | +1.6 | ||
| Astrophotography | +2.3 | ||
| Filmmaking | — |
Full spec comparison
| Spec | K-S1 | Pentax K-3 Mark III | |
|---|---|---|---|
| Price | £72 used | £1,048 used | |
| Released | 2014 | 2021 | ↑ |
| Sensor | 20.12MP APS-C CMOS | 25.7MP APS-C BSI CMOS (AA-filterless) | |
| Resolution | 20MP | 26MP | ↑ |
| Video | Full HD 1080p/30 | 4K/30p, 1080p/60p | |
| Autofocus | SAFOX IX i+ phase-detect AF, 11 points (9 cross-type) | SAFOX 13 phase-detect, 101-point (25 cross-type) | |
| Stabilisation | Sensor-shift Shake Reduction | 5.5-stop 5-axis IBIS (Shake Reduction III) | |
| Burst Rate | 5.4fps | 12fps | ↑ |
| Battery Life | ~410 shots (CIPA) | 800 shots (CIPA) | ↑ |
| Weight | 558g (with battery) | 820g (body only) | ↓ |
| Weather Sealed | Not weather sealed | Yes | ↑ |
| Viewfinder | Pentaprism, ~100%, 0.95x | Optical pentaprism, 100% coverage, 1.05× magnification | |
| Screen | 3.0" fixed LCD, 921k dots | 3.2" fixed touchscreen | |
| Mount | Pentax KAF2 (K-mount) | Pentax KF-mount | |
| Memory Cards | Single SD slot | Dual SD UHS-II |
Compare side-by-side
⚖️ Compare these cameras
See K-S1 and Pentax K-3 Mark III next to each other with our interactive comparison tool.
Get a personalised upgrade score
Run the upgrade checker →
Tell us what you shoot and we'll score the Pentax K-3 Mark III against your specific genres — not just specs.
Other upgrades from the K-S1
Camera family history