Nikon
Z9
Flagship stacked mirrorless with 45MP, 8K video, and no mechanical shutter.
$5,899
Released Oct 2021
OM System
OM-3 ASTRO
Astrophotography-focused OM-3 variant with 20.4MP stacked sensor, H-alpha-friendly filter tuning, IP53 sealing, and 7.5-stop Sync IS.
$2,499
Released Jul 2025
OM-3 ASTRO is 3.7 years newer.
Wins
Z9
Wins
OM-3 ASTRO
1 categories tied
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TL;DR — Key differences
- BOM-3 ASTRO has higher Burst (mechanical) (10 fps vs 0 fps)
- BOM-3 ASTRO has higher ISO max (native) (102,400 vs 25,600)
- BOM-3 ASTRO has lower Weight (496 g vs 1340 g)
- AZ9 has higher Resolution (45.7 MP vs 20.4 MP)
- BOM-3 ASTRO has higher AF points / zones (1053 vs 493)
Key specs at a glance
Size and weight, to scale
Z9
149 × 150 × 91 mm
1340 g (2.95 lb / 47.27 oz)
OM-3 ASTRO
139 × 89 × 46 mm
496 g (1.09 lb / 17.50 oz)
Z9 is 10mm wider, 61mm taller, and 45mm thicker than OM-3 ASTRO.
Z9 is 844 g heavier than OM-3 ASTRO.
Depth (front-to-back): 91mm Z9 · 46mm OM-3 ASTRO
Back view, to scale
Width × Height — same proportions as the front of the body.
Z9
149 × 150 mm
OM-3 ASTRO
139 × 89 mm
Top view, to scale
Width × Depth (front-to-back) — see which body is chunkier on the table.
Z9
149 × 91 mm
OM-3 ASTRO
139 × 46 mm
Sensor size, to scale
Z9
35.9 × 23.9 mm · Full Frame
858 mm² area
OM-3 ASTRO
17.4 × 13 mm · Compact / large-type
226 mm² area
3.8× larger sensor area = shallower depth of field and better low-light performance.
Lens ecosystem
Native lens selection
Z9
Nikon Z
90+
native lenses available
OM-3 ASTRO
✓ more lensesMicro Four Thirds
130+
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
Z9
Codecs
Adds N-RAW, ProRes RAW HQ, ProRes 422 HQ…
Dimensions (W×H×D mm)
Adds 149, 149.5, 90.5
Card types
Adds CFexpress Type B / XQD, CFexpress Type B / XQD
Subject recognition
Adds Dogs, Cats, Cars…
Resolution
45.7 MP vs 20.4 MP — higher is better
AF low-light limit
-8.5 EV vs -8 EV — lower is better
4K max frame rate
120 fps vs 60 fps — higher is better
Internal RAW video
Only Z9 supports it
Reasons to choose
OM-3 ASTRO
Burst (mechanical)
10 fps vs 0 fps — higher is better
Codecs
Adds H.264, H.265, MOV
Dimensions (W×H×D mm)
Adds 139.3, 88.9, 45.8
Card types
Adds SD UHS-II, SD UHS-I
ISO max (native)
102,400 vs 25,600 — higher is better
Weight
496 g vs 1340 g — lower is better
AF points / zones
1053 vs 493 — higher is better
Subject recognition
Adds Animals, Motorsports
Both cameras share
- ✓Eye AF — Both support eye af
- ✓Animal / bird AF — Both support animal / bird af
- ✓Burst (electronic) — Both 120 fps
- ✓Pre-Capture / Pre-Release — Both support pre-capture / pre-release
- ✓In-body stabilization — Both support in-body stabilization
- ✓Weather sealing — Both support weather sealing
Pros & cons at a glance
Editorially curated highlights and trade-offs.
Z9
Pros
- ✓45MP stacked
- ✓8K 60p internal
- ✓120fps stills
- ✓Pro build
Cons
- –Heavy body
- –Expensive
- –Large files
OM-3 ASTRO
Pros
- ✓Astro-tuned sensor filter
- ✓20.4MP stacked BSI Live MOS
- ✓IP53 weather sealing
- ✓7.5-stop Sync IS
Cons
- –Specialized astro variant
- –Micro Four Thirds sensor
- –Premium price
Full specifications
✓ = category winner
Frequently asked
Quick answers generated from verified specs.
Which is better for landscape, Z9 or OM-3 ASTRO?
Z9 scores 9.5/10 versus 2.5/10 for OM-3 ASTRO — 45.7MP — excellent for prints up to 24×36".
What's the resolution difference between the Z9 and OM-3 ASTRO?
Z9 is 45.7 MP and OM-3 ASTRO is 20.4 MP, so the Z9 captures more detail for cropping and large prints.
Do the Z9 and OM-3 ASTRO have in-body image stabilization?
Z9 has 6-stop in-body image stabilization, while oM-3 ASTRO has 6.5-stop in-body image stabilization.
Which shoots faster bursts — the Z9 or the OM-3 ASTRO?
Z9 reaches 120 fps electronic. OM-3 ASTRO reaches 120 fps electronic.
What's the weight difference between the Z9 and OM-3 ASTRO?
Z9 weighs 1340 g and OM-3 ASTRO weighs 496 g, so the OM-3 ASTRO is 844 g lighter.
Do the Z9 and OM-3 ASTRO record 4K video?
Z9: 8K UHD (max), 4K up to 120p. OM-3 ASTRO: 4K up to 60p.
Are the Z9 and OM-3 ASTRO weather sealed?
Z9: Yes. OM-3 ASTRO: Yes.
Which has better battery life?
Rated battery life is 740 shots (CIPA) for the Z9 and 640 shots for the OM-3 ASTRO, giving the Z9 the edge.
How much does each cost?
Z9 launched at $5,899 and OM-3 ASTRO at $2,499. The OM-3 ASTRO is $3,400 less.
Specs sourced from manufacturer data. Use-case scores algorithmically derived. Last reviewed May 2026.
Product images courtesy of Nikon and OM System press materials.