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
Launch priceReleased Jul 2025
OM System
PEN
First OM SYSTEM-branded PEN: compact rangefinder-style Micro Four Thirds body with 20.4MP Live MOS, 5-axis IBIS, built-in EVF, IPX1 sealing, and in-camera computational modes.
$1,000
Launch priceReleased Sep 2026
PEN is 1.2 years newer.
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Wins
OM-3 ASTRO
Wins
PEN
4 categories tied
Which would you choose?
TL;DR — Key differences
- AOM-3 ASTRO has higher AF points / zones (1053 vs 121)
- AOM-3 ASTRO has higher ISO max (native) (102,400 vs 25,600)
- AOM-3 ASTRO has higher Burst (electronic) (120 fps vs 30 fps)
- AOM-3 ASTRO has higher 1080p max frame rate (240 fps vs 60 fps)
- AOM-3 ASTRO has lower ISO min (native) (80 vs 200)
Key specs at a glance
Size and weight, to scale
📸 Snap this size diff to shareOM-3 ASTRO
139 × 89 × 46 mm
496 g (1.09 lb / 17.50 oz)
Credit card
85.6 × 54 mm
for scale
PEN
126 × 75 × 43 mm
393 g (0.87 lb / 13.86 oz)
OM-3 ASTRO is 14mm wider, 14mm taller, and 3mm thicker than PEN.
OM-3 ASTRO is 103 g heavier than PEN.
Depth (front-to-back): 46mm OM-3 ASTRO · 43mm PEN
Back view, to scale
Width × Height — same proportions as the front of the body.
OM-3 ASTRO
139 × 89 mm
Credit card
85.6 × 54 mm
PEN
126 × 75 mm
Top view, to scale
Width × Depth (front-to-back) — see which body is chunkier on the table.
OM-3 ASTRO
139 × 46 mm
Credit card
85.6 × 54 mm
PEN
126 × 43 mm
Sensor size, to scale
OM-3 ASTRO
17.4 × 13 mm · Compact / large-type
226 mm² area
PEN
17.4 × 13 mm · Compact / large-type
226 mm² area
Lens ecosystem
Native lens selection
OM-3 ASTRO
✓ more lensesMicro Four Thirds
130+
native lenses available
PEN
✓ 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
OM-3 ASTRO
AF low-light limit
-8 EV vs -3.5 EV — lower is better
Subject recognition
Adds People, Birds, Animals…
Dimensions (W×H×D mm)
Adds 139.3, 88.9, 45.8
Card types
Adds SD UHS-II, SD UHS-I
AF points / zones
1053 vs 121 — higher is better
ISO max (native)
102,400 vs 25,600 — higher is better
Burst (electronic)
120 fps vs 30 fps — higher is better
1080p max frame rate
240 fps vs 60 fps — higher is better
Reasons to choose
PEN
Subject recognition
Adds Human, Dog, Cat
Dimensions (W×H×D mm)
Adds 125.8, 74.5, 43.3
Card types
Adds SD, SDHC, SDXC
Max video bit rate
240 Mbps vs 150 Mbps — higher is better
Codecs
Adds MPEG-4 AVC
EVF magnification
1.1 × vs 0.78 × — higher is better
Weight
393 g vs 496 g — lower is better
Both cameras share
- ✓Resolution — Both 20.4 MP
- ✓Eye AF — Both support eye af
- ✓Animal / bird AF — Both support animal / bird af
- ✓Pre-Capture / Pre-Release — Both support pre-capture / pre-release
- ✓In-body stabilization (IBIS) — Both support in-body stabilization (ibis)
- ✓Weather sealing — Both support weather sealing
Pros & cons at a glance
Editorially curated highlights and trade-offs.
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
PEN
Pros
- ✓393g rangefinder body with built-in 2.36M-dot EVF
- ✓First PEN with IPX1 dust/splash sealing
- ✓5-axis IBIS up to 5.5 stops + 121-point cross-type AF
- ✓Hi-Res, Live ND, Focus Stacking, HDR via CP button
- ✓4K / C4K video, vertical video, 3.5mm mic jack
Cons
- –Micro Four Thirds sensor vs APS-C/FF rivals
- –4K capped at 30p (C4K 24p only)
- –IPX1 is lighter sealing than OM-5 II / OM-3
- –Single SD slot, no headphone jack
Decided which one is right for you?
Compare live prices for the OM-3 ASTRO and PEN at major authorized retailers.
OM System OM-3 ASTRO
OM System PEN
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Full specifications
✓ = category winner
Frequently asked
Quick answers generated from verified specs.
Which is better for sports, OM-3 ASTRO or PEN?
OM-3 ASTRO scores 10.0/10 versus 6.0/10 for PEN — 120fps burst — pro-level action capture.
What's the resolution difference between the OM-3 ASTRO and PEN?
Both cameras share the same 20.4 MP resolution.
Do the OM-3 ASTRO and PEN have in-body image stabilization?
OM-3 ASTRO has 6.5-stop in-body image stabilization, while PEN has 5.5-stop in-body image stabilization.
Which shoots faster bursts — the OM-3 ASTRO or the PEN?
OM-3 ASTRO reaches 120 fps electronic. PEN reaches 30 fps electronic.
What's the weight difference between the OM-3 ASTRO and PEN?
OM-3 ASTRO weighs 496 g and PEN weighs 393 g, so the PEN is 103 g lighter.
Do the OM-3 ASTRO and PEN record 4K video?
OM-3 ASTRO: 4K up to 60p. PEN: 4K up to 30p.
Are the OM-3 ASTRO and PEN weather sealed?
OM-3 ASTRO: Yes. PEN: Yes.
Which has better battery life?
Rated battery life is 640 shots (CIPA) for the OM-3 ASTRO and 410 shots for the PEN, giving the OM-3 ASTRO the edge.
How much does each cost?
OM-3 ASTRO launched at $2,499 and PEN at $1,000. The PEN is $1,499 less.
Can't decide between two? Compare a third camera.
Add any camera to get a three-way OM-3 ASTRO vs PEN vs X comparison.
Specs sourced from manufacturer data. Use-case scores algorithmically derived. Last reviewed September 2026.
Product images courtesy of OM System press materials.