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OM-3

OM System

OM-3

Retro-styled MFT body with modern AF and creator-friendly design.

$1,699

Launch price

Released Jan 2025

vs
Alpha 7 IV

Sony

Alpha 7 IV

33MP hybrid all-rounder with 10-bit 4K 60p and AI-powered subject tracking.

$2,499

Launch price

Released Oct 2021

OM-3 is 3.3 years newer.

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Wins

8categories

OM-3

Sports & ActionTravel

Wins

7categories

Alpha 7 IV

PortraitWildlife

2 categories tied

Which would you choose?

TL;DR — Key differences

OM-3 wins 1 categories·Alpha 7 IV wins 4 categories
  • AOM-3 has higher Burst (electronic) (120 fps vs 10 fps)
  • BAlpha 7 IV has higher Max video bit rate (600 Mbps vs 205 Mbps)
  • BAlpha 7 IV has lower ISO min (native) (100 vs 200)
  • BAlpha 7 IV has higher ISO max (native) (51,200 vs 25,600)
  • BAlpha 7 IV has higher Card slots (2 vs 1)

Key specs at a glance

OM-3Alpha 7 IV
Resolution20.4 MP33 MP
SensorMFTFull Frame
ISO max25,60051,200
Burst120 fps10 fps
4K59.94 fps60 fps
IBIS6.5-stop5.5-stop
Weight413 g658 g
Battery640 shots580 shots

Size and weight, to scale

OM-3 front view

OM-3

139 × 89 × 46 mm

413 g (0.91 lb / 14.57 oz)

Credit card shown to scale as a size reference (ISO 7810, 85.6 × 54 mm)

Credit card

85.6 × 54 mm

for scale

Alpha 7 IV front view

Alpha 7 IV

131 × 96 × 80 mm

658 g (1.45 lb / 23.21 oz)

OM-3 is 8mm shorter and 34mm thinner than Alpha 7 IV but it is also 8mm wider.

OM-3 is 245 g lighter than Alpha 7 IV.

Depth (front-to-back): 46mm OM-3 · 80mm Alpha 7 IV

Back view, to scale

Width × Height — same proportions as the front of the body.

OM-3 back view

OM-3

139 × 89 mm

Credit card shown to scale as a size reference (ISO 7810, 85.6 × 54 mm)

Credit card

85.6 × 54 mm

Alpha 7 IV back view

Alpha 7 IV

131 × 96 mm

Top view, to scale

Width × Depth (front-to-back) — see which body is chunkier on the table.

OM-3 top view

OM-3

139 × 46 mm

Credit card shown to scale as a size reference (ISO 7810, 85.6 × 54 mm)

Credit card

85.6 × 54 mm

Alpha 7 IV top view

Alpha 7 IV

131 × 80 mm

Sensor size, to scale

OM-3

17.4 × 13 mm · Compact / large-type

226 mm² area

Alpha 7 IV

35.9 × 23.9 mm · Full Frame

858 mm² area

3.8× larger sensor area = shallower depth of field and better low-light performance.

Lens ecosystem

Native lens selection

OM-3

Micro Four Thirds

130+

native lenses available

60 first-party70 third-party

Alpha 7 IV

✓ more lenses

Sony E

350+

native lenses available

80 first-party270 third-party

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

Use caseOM-3Alpha 7 IV
Portrait
4.0Fair
9.0Excellent✓ wins
Sports & Action
8.5Excellent✓ wins
6.5Good
Video & Hybrid
3.5Limited
7.5Good✓ wins
Landscape
2.5Limited
7.5Good✓ wins
Travel
8.0Excellent✓ wins
7.0Good
Wildlife
5.5Fair
8.0Excellent✓ wins
Vlogging
6.5Good
8.0Excellent✓ wins

Why pick one over the other

Reasons to choose

OM-3

  • AF low-light limit

    -5.5 EV vs -4 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, SDHC, SDXC

  • Burst (electronic)

    120 fps vs 10 fps — higher is better

  • Pre-Capture / Pre-Release

    Only OM-3 supports it

  • Codecs

    Adds MOV, MPEG-4 AVC

  • Weight

    413 g vs 658 g — lower is better

Reasons to choose

Alpha 7 IV

  • Subject recognition

    Adds Human, Animal, Bird…

  • Dimensions (W×H×D mm)

    Adds 131.3, 96.4, 79.8

  • Card types

    Adds CFexpress Type A, SD UHS-II

  • Max video bit rate

    600 Mbps vs 205 Mbps — higher is better

  • Codecs

    Adds XAVC HS, XAVC S, XAVC S-I

  • AA filter

    Only Alpha 7 IV supports it

  • ISO min (native)

    100 vs 200 — lower is better

  • ISO max (native)

    51,200 vs 25,600 — higher is better

Both cameras share

  • Eye AFBoth support eye af
  • Animal / bird AFBoth support animal / bird af
  • Burst (mechanical)Both 10 fps
  • In-body stabilization (IBIS)Both support in-body stabilization (ibis)
  • Weather sealingBoth support weather sealing
  • EVF refresh rateBoth 120 Hz

Pros & cons at a glance

Editorially curated highlights and trade-offs.

OM-3

Pros

  • Retro design
  • Modern AF
  • Compact

Cons

  • MFT sensor
  • Premium for MFT
  • Smaller lens selection

Alpha 7 IV

Pros

  • 33MP — more detail for cropping and print
  • 10-bit 4K 60p (Super35 crop) / 4K 30p full-frame
  • Full-size HDMI port
  • 759 phase-detect AF points

Cons

  • 4K 60p requires Super35 crop
  • 10fps burst lags behind R6 II at 40fps
  • Complex menu system

Decided which one is right for you?

Compare live prices for the OM-3 and Alpha 7 IV at major authorized retailers.

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Full specifications

= category winner

OM-3
Alpha 7 IV
Resolution
20.4 MP
33 MP+62%
Sensor type
BSI Stacked MOS
Full Frame Exmor R CMOS
Sensor size
17.4 x 13
35.9 × 23.9 mm
AA filter
No
Yes
OM-3
Alpha 7 IV
Processor
TruePic X
BIONZ XR
OM-3
Alpha 7 IV
ISO min (native)
200
100−100 less
ISO max (native)
25,600
51,200+1 stop
ISO max (expanded)
102,400
204,800
OM-3
Alpha 7 IV
Shutter type
Mechanical Focal Plane Shutter and Electronic Rolling Shutter
Mechanical + Electronic
Max mechanical speed
1/8000
1/8000 sec
Max electronic speed
1/32000
1/8000 sec

Frequently asked

Quick answers generated from verified specs.

Which is better for portraits, OM-3 or Alpha 7 IV?

Alpha 7 IV scores 9.0/10 versus 4.0/10 for OM-3 — 33MP — ample resolution for portraits.

What's the resolution difference between the OM-3 and Alpha 7 IV?

OM-3 is 20.4 MP and Alpha 7 IV is 33 MP, so the Alpha 7 IV captures more detail for cropping and large prints.

Do the OM-3 and Alpha 7 IV have in-body image stabilization?

OM-3 has 6.5-stop in-body image stabilization, while Alpha 7 IV has 5.5-stop in-body image stabilization.

Which shoots faster bursts — the OM-3 or the Alpha 7 IV?

OM-3 reaches 120 fps electronic. Alpha 7 IV reaches 10 fps electronic.

What's the weight difference between the OM-3 and Alpha 7 IV?

OM-3 weighs 413 g and Alpha 7 IV weighs 658 g, so the OM-3 is 245 g lighter.

Do the OM-3 and Alpha 7 IV record 4K video?

OM-3: 4K up to 59.94p. Alpha 7 IV: 4K up to 60p.

Are the OM-3 and Alpha 7 IV weather sealed?

OM-3: Yes. Alpha 7 IV: Yes.

Which has better battery life?

Rated battery life is 640 shots (CIPA) for the OM-3 and 580 shots for the Alpha 7 IV, giving the OM-3 the edge.

How much does each cost?

OM-3 launched at $1,699 and Alpha 7 IV at $2,499. The OM-3 is $800 less.

Can't decide between two? Compare a third camera.

Add any camera to get a three-way OM-3 vs Alpha 7 IV vs X comparison.

Specs sourced from manufacturer data. Use-case scores algorithmically derived. Last reviewed July 2026.

Product images courtesy of OM System and Sony press materials.