EOS R100vs A7R III
Canon
EOS R100 (2023)
Starting from £529 new
Best for First camera / beginner photography
View EOS R100
Sony
A7R III (2017)
Starting from £1799 new
Best for Landscape, studio & commercial photography
View A7R III
GearScore™ Verdict — 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.
Landscape, Studio & Commercial Photography — A7R III (2017): The camera that converted professionals to mirrorless — 42MP, IBIS, and 10fps in a body that still competes today.
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
A7R III (2017)
- Landscape and studio photographers who need 42MP resolution at a used-price discount vs A7R IV
- Canon/Nikon DSLR professionals considering a mirrorless switch at a lower investment
- Commercial and product photographers who want full-frame resolution with IBIS for handheld work
- Portrait photographers who want the sharpest possible full-frame files for large print work
Quick take: The a7r iii has the highest resolution at 42mp; the eos r100 is the most affordable; only the a7r iii is weather sealed. Scroll down for the full spec breakdown.
Full specifications
| Specification | EOS R100 (2023) | A7R III (2017) |
|---|---|---|
| Price | £529 | £1,799 |
| Sensor | 24.1MP APS-C CMOS | 42.4MP full-frame BSI Exmor R CMOS |
| Resolution | 24.1MP | 42.4MP |
| Video | 4K/30p (slight crop), 1080p/60p | 4K/30p (full-frame readout), 1080p/120p |
| Autofocus | Dual Pixel CMOS AF, face detection, subject tracking | 399 phase-detect + 425 contrast AF points — real-time Eye AF |
| Stabilisation | None (no IBIS) | 5-axis IBIS — 5.5 stops |
| Burst Rate | 6.5fps mechanical | 10fps with AF/AE tracking |
| Battery Life | ~270 shots (CIPA) | ~650 shots (CIPA) |
| Weight | 356g (body, battery, card) | 650g body only |
| Dimensions | 116.3 × 85.5 × 68.8mm | 126.9 × 95.6 × 73.7mm |
| Weather Sealed | No | Yes |
| Viewfinder | EVF, 2.36M dots, 0.59× magnification | EVF, 3.69M dots, 0.78× magnification |
| Screen | 3.0" fixed touchscreen, 1.04M dots | 3.0" touchscreen, tilting |
| Mount | Canon RF-mount | Sony FE mount (full-frame E-mount) |
| Memory Cards | Single SD UHS-II | Dual SD slots (one UHS-II) |
| Connectivity | USB-C, Wi-Fi, Bluetooth | USB-C, Bluetooth, Wi-Fi, 3.5mm mic jack |
Suitability by genre
| Genre | EOS R100 | A7R III |
|---|---|---|
| Portrait | ||
| Travel | — | |
| Street | ||
| Video | — | |
| Wildlife | — | |
| Landscape | — | |
| Vlogging & Video | — | |
| Wedding | — | |
| Sports | — |
More comparisons with EOS R100
Camera family history