DJI
Osmo Action 4
1/1.3-inch sensor action camera with 10-bit D-Log M and strong stabilization.
$299
Released Aug 2023
Sony
Alpha 9
First stacked-sensor mirrorless sports camera with 20fps blackout-free shooting.
$4,499
Released Apr 2017
Osmo Action 4 is 6.3 years newer.
Wins
Osmo Action 4
Wins
Alpha 9
1 categories tied
TL;DR — Key differences
- BAlpha 9 has higher AF points / zones (693 vs 0)
- AOsmo Action 4 has lower Weight (145 g vs 673 g)
- BAlpha 9 has higher ISO max (native) (51,200 vs 12,800)
- AOsmo Action 4 has higher 4K max frame rate (120 fps vs 30 fps)
- BAlpha 9 has higher RAW buffer depth (200 frames vs 60 frames)
Key specs at a glance
Size and weight, to scale
Osmo Action 4
71 × 44 × 33 mm
145 g (0.32 lb / 5.11 oz)
Alpha 9
127 × 96 × 63 mm
673 g (1.48 lb / 23.74 oz)
Osmo Action 4 is 56mm narrower, 51mm shorter, and 30mm thinner than Alpha 9.
Osmo Action 4 is 528 g lighter than Alpha 9.
Depth (front-to-back): 33mm Osmo Action 4 · 63mm Alpha 9
Sensor size, to scale
Alpha 9
35.6 × 23.8 mm · Full Frame
847 mm² area
Lens ecosystem
Native lens selection
Osmo Action 4: mount data unavailable
Alpha 9
✓ more lensesSony E
350+
native lenses available
Counts include current first-party and major third-party native autofocus lenses.
Use-case scoring
Which one for what?
Algorithmic scores from verified specs · 10 = best in class
Why pick one over the other
Reasons to choose
Osmo Action 4
Dimensions (W×H×D mm)
Adds 70.5, 44.2, 32.8
Card types
Adds microSD
Weight
145 g vs 673 g — lower is better
4K max frame rate
120 fps vs 30 fps — higher is better
Pre-Capture / Pre-Release
Only Osmo Action 4 supports it
Codecs
Adds HEVC
Max video bit rate
200 Mbps vs 150 Mbps — higher is better
Burst (mechanical)
6 fps vs 5 fps — higher is better
Reasons to choose
Alpha 9
AF points / zones
693 vs 0 — higher is better
Subject recognition
Adds Human, Animal
Dimensions (W×H×D mm)
Adds 126.9, 95.6, 63
Card types
Adds SD UHS-II, SD UHS-I
ISO max (native)
51,200 vs 12,800 — higher is better
RAW buffer depth
200 frames vs 60 frames — higher is better
Codecs
Adds XAVC S, AVCHD
Resolution
24.2 MP vs 10 MP — higher is better
Both cameras share
- ✓ISO min (native) — Both 100
- ✓Weather sealing — Both support weather sealing
- ✓Touchscreen — Both support touchscreen
- ✓Wi-Fi — Both support wi-fi
- ✓Bluetooth — Both support bluetooth
Pros & cons at a glance
Editorially curated highlights and trade-offs.
Osmo Action 4
Pros
- ✓10-bit D-Log M
- ✓Good low light for action cam
- ✓Affordable
Cons
- –Superseded by Action 5 Pro
- –Fixed lens
Alpha 9
Pros
- ✓Stacked sensor pioneer
- ✓20fps silent burst
- ✓Pro sports AF
Cons
- –Superseded by A9 II/III
- –24MP
- –Expensive when new
Full specifications
✓ = category winner
Frequently asked
Quick answers generated from verified specs.
Which is better for portraits, Osmo Action 4 or Alpha 9?
Alpha 9 scores 7.5/10 versus 1.0/10 for Osmo Action 4 — 24.2MP — solid resolution.
What's the resolution difference between the Osmo Action 4 and Alpha 9?
Osmo Action 4 is 10 MP and Alpha 9 is 24.2 MP, so the Alpha 9 captures more detail for cropping and large prints.
Do the Osmo Action 4 and Alpha 9 have in-body image stabilization?
Osmo Action 4 does not have IBIS, while alpha 9 has 5-stop in-body image stabilization.
Which shoots faster bursts — the Osmo Action 4 or the Alpha 9?
Osmo Action 4 reaches 15 fps electronic. Alpha 9 reaches 20 fps electronic.
What's the weight difference between the Osmo Action 4 and Alpha 9?
Osmo Action 4 weighs 145 g and Alpha 9 weighs 673 g, so the Osmo Action 4 is 528 g lighter.
Do the Osmo Action 4 and Alpha 9 record 4K video?
Osmo Action 4: 4K up to 120p. Alpha 9: 4K up to 30p.
Are the Osmo Action 4 and Alpha 9 weather sealed?
Osmo Action 4: Yes. Alpha 9: Yes.
Which has better battery life?
Rated battery life is 640 shots (CIPA) for the Osmo Action 4 and 650 shots for the Alpha 9, giving the Alpha 9 the edge.
How much does each cost?
Osmo Action 4 launched at $299 and Alpha 9 at $4,499. The Osmo Action 4 is $4,200 less.
Specs sourced from manufacturer data. Use-case scores algorithmically derived. Last reviewed May 2026.