Where they actually differ
The most decisive specs, ranked by how much they matter — before the full spec table.
| Spec | Canon - EOS R5 Mark II | Sony - α9 III |
|---|---|---|
| Megapixels | 45 MP | 24 MP |
| Weight | 746 g | 703 g |
| AF points | 1053 | 759 |
| Max video | 8K | 4K120 |
Between the EOS R5 Mark II and α9 III, the EOS R5 Mark II comes out ahead in megapixels / af points, while the α9 III wins on weight. Overall, the EOS R5 Mark II scores 81.8 and the α9 III scores 71.7 on our Mars Score.
Which should you buy?
The EOS R5 Mark II is the clear pick on raw spec strength, leading by 10.1 points on the Mars Score. The margin is wide enough that the underdog only makes sense if its individual strengths line up with what you specifically need.
Pick the EOS R5 Mark II if you care most about megapixels / af points. The biggest gaps in its favor are megapixels, af points, max video. The single most decisive one: Megapixels — 87.50% more. 45 MP vs 24 MP.
Pick the α9 III if you carry the device everywhere and weight or thickness has been the deciding factor before. Its strongest claims are weight. The single most decisive one: Weight — 43.00 g less. 703 vs 746.
Both ship with comparable sensor size, in-body stabilization, log profile, so those specs do not separate the two — focus on the differences below.
Bottom line: the EOS R5 Mark II is the safer default. The other model is the right choice only when its specific advantages line up with your priorities.
Which should you buy: Canon - EOS R5 Mark II or Sony - α9 III?
Canon - EOS R5 Mark II leads the current Mars Score by 10.1 points.The more useful decision is the trade-off behind that result: compare megapixels, max video, weight against the way you will actually use the product.
Choose Canon - EOS R5 Mark II if…
Canon - EOS R5 Mark II has the measurable edge on megapixels, af points, max video.
Choose Sony - α9 III if…
Sony - α9 III has the measurable edge on weight g.
This is a structured comparison of the published catalog values. It is not a claim of identical real-world performance across every workload; use the linked spec drill-downs and methodology page to inspect the inputs.
Why Canon - EOS R5 Mark II wins
- ▲Megapixels — 87.50% more. 45 MP vs 24 MP.
- ▲AF points — 38.74% more. 1053 vs 759.
- ▲Max video: 8K (vs 4K120).
Why Sony - α9 III wins
- ▲Weight — 43.00 g less. 703 vs 746.
Spec comparison
Sensor
| Spec | Canon - EOS R5 Mark II | Sony - α9 III |
|---|---|---|
| Sensor sizeⓘ | Full Frame | Full Frame |
| Megapixels | 45 MPlead | 24 MP |
| Max ISO | 102400lead | 51200 |
Video
| Spec | Canon - EOS R5 Mark II | Sony - α9 III |
|---|---|---|
| Max video | 8Klead | 4K120 |
| RAW video | true | true |
| Log profileⓘ | true | true |
Autofocus
| Spec | Canon - EOS R5 Mark II | Sony - α9 III |
|---|---|---|
| AF pointsⓘ | 1053lead | 759 |
| Eye AFⓘ | true | true |
| In-body stabilizationⓘ | true | true |
Body & Controls
| Spec | Canon - EOS R5 Mark II | Sony - α9 III |
|---|---|---|
| Weight | 746 g | 703 glead |
| Weather sealedⓘ | true | true |
| Dual card slotsⓘ | true | true |