OM System
OM-1 II
Flagship MFT with stacked sensor, 120fps, and pro wildlife features.
$2,399
Released Feb 2024
Pentax
K-3 Mark III
APS-C DSLR flagship with optical viewfinder and weather sealing.
$1,999
Released Apr 2021
OM-1 II is 2.8 years newer.
Wins
OM-1 II
Wins
K-3 Mark III
5 categories tied
TL;DR — Key differences
- AOM-1 II has higher AF points / zones (1053 vs 101)
- AOM-1 II has higher Burst (electronic) (120 fps vs 20 fps)
- AOM-1 II has higher ISO max (native) (102,400 vs 25,600)
- BK-3 Mark III has higher Card slots (2 vs 1)
- AOM-1 II has higher EVF resolution (5,760,000 vs 3,690,000)
Key specs at a glance
Size and weight, to scale
OM-1 II
135 × 92 × 73 mm
599 g (1.32 lb / 21.13 oz)
K-3 Mark III
138 × 98 × 88 mm
520 g (1.15 lb / 18.34 oz)
OM-1 II is 3mm narrower, 6mm shorter, and 15mm thinner than K-3 Mark III.
OM-1 II is 79 g heavier than K-3 Mark III.
Depth (front-to-back): 73mm OM-1 II · 88mm K-3 Mark III
Sensor size, to scale
OM-1 II
17.4 × 13 mm · Compact / large-type
226 mm² area
K-3 Mark III
23.5 × 15.6 mm · APS-C
367 mm² area
1.6× larger sensor area = shallower depth of field and better low-light performance.
Lens ecosystem
Native lens selection
OM-1 II
✓ more lensesMicro Four Thirds
130+
native lenses available
K-3 Mark III
Pentax K
70+
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-1 II
AF low-light limit
-8 EV vs -3 EV — lower is better
Subject recognition
Adds People, Birds, Animals…
Dimensions (W×H×D mm)
Adds 134.8, 91.6, 72.7
AF points / zones
1053 vs 101 — higher is better
Burst (electronic)
120 fps vs 20 fps — higher is better
ISO max (native)
102,400 vs 25,600 — higher is better
Card types
Adds SD UHS-I
EVF resolution
5,760,000 vs 3,690,000 — higher is better
Reasons to choose
K-3 Mark III
Subject recognition
Adds Human, Animal, Bird…
Dimensions (W×H×D mm)
Adds 138, 98, 88
Card slots
2 vs 1 — higher is better
Headphone jack (3.5mm)
Only K-3 Mark III supports it
Resolution
25.7 MP vs 20.4 MP — higher is better
Battery life (CIPA)
640 shots vs 520 shots — higher is better
Weight
520 g vs 599 g — lower is better
Both cameras share
- ✓AF frame coverage — Both 100 %
- ✓Eye AF — Both support eye af
- ✓Animal / bird AF — Both support animal / bird af
- ✓Pre-Capture / Pre-Release — Both support pre-capture / pre-release
- ✓4K max frame rate — Both 60 fps
- ✓Max video bit rate — Both 150 Mbps
Pros & cons at a glance
Editorially curated highlights and trade-offs.
OM-1 II
Pros
- ✓120fps stills
- ✓Stacked MFT
- ✓IP53 weather sealing
- ✓Computational features
Cons
- –MFT sensor size
- –Smaller ecosystem
- –Menu complexity
K-3 Mark III
Pros
- ✓Optical viewfinder
- ✓Weather sealed
- ✓IBIS in DSLR
Cons
- –DSLR system declining
- –APS-C
- –Limited video
Full specifications
✓ = category winner
Frequently asked
Quick answers generated from verified specs.
Which is better for wildlife, OM-1 II or K-3 Mark III?
K-3 Mark III scores 10.0/10 versus 6.5/10 for OM-1 II — 20fps burst captures fleeting moments.
What's the resolution difference between the OM-1 II and K-3 Mark III?
OM-1 II is 20.4 MP and K-3 Mark III is 25.7 MP, so the K-3 Mark III captures more detail for cropping and large prints.
Do the OM-1 II and K-3 Mark III have in-body image stabilization?
OM-1 II has 8.5-stop in-body image stabilization, while k-3 Mark III has 7-stop in-body image stabilization.
Which shoots faster bursts — the OM-1 II or the K-3 Mark III?
OM-1 II reaches 120 fps electronic. K-3 Mark III reaches 20 fps electronic.
What's the weight difference between the OM-1 II and K-3 Mark III?
OM-1 II weighs 599 g and K-3 Mark III weighs 520 g, so the K-3 Mark III is 79 g lighter.
Do the OM-1 II and K-3 Mark III record 4K video?
OM-1 II: 4K up to 60p. K-3 Mark III: 4K up to 60p.
Are the OM-1 II and K-3 Mark III weather sealed?
OM-1 II: Yes. K-3 Mark III: Yes.
Which has better battery life?
Rated battery life is 520 shots (CIPA) for the OM-1 II and 640 shots for the K-3 Mark III, giving the K-3 Mark III the edge.
How much does each cost?
OM-1 II launched at $2,399 and K-3 Mark III at $1,999. The K-3 Mark III is $400 less.
Specs sourced from manufacturer data. Use-case scores algorithmically derived. Last reviewed May 2026.