Where they actually differ
The most decisive specs, ranked by how much they matter — before the full spec table.
| Spec | OM System - OM-1 Mark II | Sony - α1 II |
|---|---|---|
| Megapixels | 20 MP | 50 MP |
| Weight | 599 g | 743 g |
| AF points | 1053 | 759 |
| Sensor size | Four Thirds | Full Frame |
| Max video | 4K60 | 8K |
Between the OM-1 Mark II and α1 II, the OM-1 Mark II comes out ahead in weight / af points, while the α1 II wins on megapixels / sensor size. Overall, the OM-1 Mark II scores 67.4 and the α1 II scores 79.6 on our Mars Score.
Which should you buy?
The α1 II is the clear pick on raw spec strength, leading by 12.2 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 OM-1 Mark II if you carry the device everywhere and weight or thickness has been the deciding factor before. The biggest gaps in its favor are weight, af points. The single most decisive one: Weight — 144.00 g less. 599 vs 743.
Pick the α1 II if you care most about megapixels / sensor size. Its strongest claims are megapixels, sensor size, max video. The single most decisive one: Megapixels — 150.00% more. 50 MP vs 20 MP.
Both ship with comparable in-body stabilization, log profile, so those specs do not separate the two — focus on the differences below.
Bottom line: the α1 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: OM System - OM-1 Mark II or Sony - α1 II?
Sony - α1 II leads the current Mars Score by 12.2 points.The more useful decision is the trade-off behind that result: compare megapixels, sensor size, max video, weight against the way you will actually use the product.
Choose OM System - OM-1 Mark II if…
OM System - OM-1 Mark II has the measurable edge on weight g, af points.
Choose Sony - α1 II if…
Sony - α1 II has the measurable edge on megapixels, sensor size, max video.
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 OM System - OM-1 Mark II wins
- ▲Weight — 144.00 g less. 599 vs 743.
- ▲AF points — 38.74% more. 1053 vs 759.
Why Sony - α1 II wins
- ▲Megapixels — 150.00% more. 50 MP vs 20 MP.
- ▲Sensor size: Full Frame (vs Four Thirds).
- ▲Max video: 8K (vs 4K60).
Spec comparison
Sensor
| Spec | OM System - OM-1 Mark II | Sony - α1 II |
|---|---|---|
| Sensor sizeⓘ | Four Thirds | Full Framelead |
| Megapixels | 20 MP | 50 MPlead |
| Max ISO | 102400 | 102400 |
Video
| Spec | OM System - OM-1 Mark II | Sony - α1 II |
|---|---|---|
| Max video | 4K60 | 8Klead |
| RAW video | false | truelead |
| Log profileⓘ | true | true |
Autofocus
| Spec | OM System - OM-1 Mark II | Sony - α1 II |
|---|---|---|
| AF pointsⓘ | 1053lead | 759 |
| Eye AFⓘ | true | true |
| In-body stabilizationⓘ | true | true |
Body & Controls
| Spec | OM System - OM-1 Mark II | Sony - α1 II |
|---|---|---|
| Weight | 599 glead | 743 g |
| Weather sealedⓘ | true | true |
| Dual card slotsⓘ | true | true |