EOS R100vs Pentax K-3 Mark IIIvs A7 IV
Pentax
Pentax K-3 Mark III (2021)
From £1699
Best for DSLR enthusiasts & outdoor photographers
View Pentax K-3 Mark III
Which should you buy?
First Camera / Beginner Photography — EOS R100 (2023): The R100 does the basics well at the lowest possible price point. Its main value is as a gateway into the Canon RF ecosystem — the lenses you buy now will work on any Canon body you upgrade to later. Modest ambitions, reliably met.
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.
Portrait & Wedding Photography — A7 IV (2021): The full-frame portrait benchmark — 33MP, AI Eye AF, and exceptional skin-tone rendering in a pro-grade hybrid body.
Who should buy what
EOS R100 (2023)
- First-time camera buyers stepping up from a smartphone
- Students and hobbyists wanting an affordable starting point
- Anyone who wants to start investing in Canon RF glass on a budget
- Casual photographers who don't need advanced video or speed
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
A7 IV (2021)
- You want a high-resolution full-frame all-rounder for portraits, weddings, or travel
- You're stepping up from APS-C or a DSLR and want the best all-round full-frame body under £3,000
- You shoot a mix of stills and video and need a single body that handles both seriously
- You want access to the widest lens ecosystem in the mirrorless market
Quick take: The a7 iv has the highest resolution at 33mp; the eos r100 is the most affordable; only the pentax k-3 mark iii, a7 iv are weather sealed. Scroll down for the full spec breakdown.
Full specifications
| Specification | EOS R100 (2023) | Pentax K-3 Mark III (2021) | A7 IV (2021) |
|---|---|---|---|
| Price | £529 | £1,699 | £2,299 |
| Sensor | 24.1MP APS-C CMOS | 25.7MP APS-C BSI CMOS (AA-filterless) | 33MP Full-frame BSI Exmor R CMOS |
| Resolution | 24.1MP | 25.7MP | 33.0MP |
| Video | 4K/30p (slight crop), 1080p/60p | 4K/30p, 1080p/60p | 4K/60p oversampled, 10-bit internal, S-Log3, S-Cinetone |
| Autofocus | Dual Pixel CMOS AF, face detection, subject tracking | SAFOX 13 phase-detect, 101-point (25 cross-type) | 759-point phase-detect, AI subject recognition |
| Stabilisation | None (no IBIS) | 5.5-stop 5-axis IBIS (Shake Reduction III) | 5-axis IBIS, 5.5 stops |
| Burst Rate | 6.5fps mechanical | 12fps | 10fps mechanical, 30fps electronic |
| Battery Life | ~270 shots (CIPA) | 800 shots (CIPA) | ~580 shots (CIPA) |
| Weight | 356g (body, battery, card) | 820g body only | 659g body only |
| Dimensions | 116.3 × 85.5 × 68.8mm | 134.5 × 103.5 × 73.5mm | 131.3 × 96.4 × 79.8mm |
| Weather Sealed | No | Yes | Yes |
| Viewfinder | EVF, 2.36M dots, 0.59× magnification | Optical pentaprism, 100% coverage, 1.05× magnification | EVF, 3.69M dots, 0.78× magnification |
| Screen | 3.0" fixed touchscreen, 1.04M dots | 3.2" tilting touchscreen | 3.0" vari-angle touchscreen |
| Mount | Canon RF-mount | Pentax KF-mount | Sony FE (full-frame E-mount) |
| Memory Cards | Single SD UHS-II | Dual SD UHS-II | Dual slots: CFexpress Type A + SD UHS-II |
| Connectivity | USB-C, Wi-Fi, Bluetooth | USB-C, Wi-Fi, Bluetooth | USB-C (3.2 Gen 2), Bluetooth, Wi-Fi |
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