Pentax
K-3 Mark III
APS-C DSLR flagship with optical viewfinder and weather sealing.
$1,999
Launch priceReleased Apr 2021
Sony
Alpha 9 III
Global shutter sports flagship with 120fps and zero rolling shutter for pro action.
$5,999
Launch priceReleased Jan 2024
Alpha 9 III is 2.8 years newer.
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Wins
K-3 Mark III
Wins
Alpha 9 III
2 categories tied
Which would you choose?
TL;DR — Key differences
- AK-3 Mark III has higher Burst (mechanical) (8 fps vs 0 fps)
- BAlpha 9 III has higher AF points / zones (759 vs 101)
- BAlpha 9 III has higher Burst (electronic) (120 fps vs 20 fps)
- BAlpha 9 III has higher Max video bit rate (600 Mbps vs 150 Mbps)
- BAlpha 9 III has higher EVF resolution (9,437,184 vs 3,690,000)
Key specs at a glance
Size and weight, to scale
📸 Snap this size diff to shareK-3 Mark III
138 × 98 × 88 mm
520 g (1.15 lb / 18.34 oz)
Credit card
85.6 × 54 mm
for scale
Alpha 9 III
136 × 97 × 83 mm
703 g (1.55 lb / 24.80 oz)
K-3 Mark III is 2mm wider, 1mm taller, and 5mm thicker than Alpha 9 III.
K-3 Mark III is 183 g lighter than Alpha 9 III.
Depth (front-to-back): 88mm K-3 Mark III · 83mm Alpha 9 III
Sensor size, to scale
K-3 Mark III
23.5 × 15.6 mm · APS-C
367 mm² area
Alpha 9 III
35.6 × 23.8 mm · Full Frame
847 mm² area
2.3× larger sensor area = shallower depth of field and better low-light performance.
Lens ecosystem
Native lens selection
K-3 Mark III
Pentax K
70+
native lenses available
Alpha 9 III
✓ 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
K-3 Mark III
Burst (mechanical)
8 fps vs 0 fps — higher is better
Dimensions (W×H×D mm)
Adds 138, 98, 88
ISO min (native)
100 vs 250 — lower is better
Battery life (CIPA)
640 shots vs 400 shots — higher is better
Weight
520 g vs 703 g — lower is better
Subject recognition
Adds Vehicle
AF frame coverage
100 % vs 94 % — higher is better
Resolution
25.7 MP vs 24.6 MP — higher is better
Reasons to choose
Alpha 9 III
AF low-light limit
-5 EV vs -3 EV — lower is better
Dimensions (W×H×D mm)
Adds 136.1, 96.9, 82.9
AF points / zones
759 vs 101 — higher is better
Burst (electronic)
120 fps vs 20 fps — higher is better
Max video bit rate
600 Mbps vs 150 Mbps — higher is better
EVF resolution
9,437,184 vs 3,690,000 — higher is better
Codecs
Adds XAVC HS, XAVC S, XAVC S-I
AA filter
Only Alpha 9 III supports it
Both cameras share
- ✓ISO max (native) — Both 25,600
- ✓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.
K-3 Mark III
Pros
- ✓Optical viewfinder
- ✓Weather sealed
- ✓IBIS in DSLR
Cons
- –DSLR system declining
- –APS-C
- –Limited video
Alpha 9 III
Pros
- ✓Global shutter 120fps
- ✓Zero rolling shutter
- ✓Pro sports AF
- ✓Pre-capture buffer
Cons
- –24.6MP only
- –Premium price
- –Battery drain at max speed
Decided which one is right for you?
Compare live prices for the K-3 Mark III and Alpha 9 III at major authorized retailers.
Pentax K-3 Mark III
Sony Alpha 9 III
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Full specifications
✓ = category winner
Frequently asked
Quick answers generated from verified specs.
Which is better for sports, K-3 Mark III or Alpha 9 III?
Alpha 9 III scores 10.0/10 versus 6.5/10 for K-3 Mark III — 120fps burst — pro-level action capture.
What's the resolution difference between the K-3 Mark III and Alpha 9 III?
K-3 Mark III is 25.7 MP and Alpha 9 III is 24.6 MP, so the K-3 Mark III captures more detail for cropping and large prints.
Do the K-3 Mark III and Alpha 9 III have in-body image stabilization?
K-3 Mark III has 7-stop in-body image stabilization, while Alpha 9 III has 8-stop in-body image stabilization.
Which shoots faster bursts — the K-3 Mark III or the Alpha 9 III?
K-3 Mark III reaches 20 fps electronic. Alpha 9 III reaches 120 fps electronic.
What's the weight difference between the K-3 Mark III and Alpha 9 III?
K-3 Mark III weighs 520 g and Alpha 9 III weighs 703 g, so the K-3 Mark III is 183 g lighter.
Do the K-3 Mark III and Alpha 9 III record 4K video?
K-3 Mark III: 4K up to 60p. Alpha 9 III: 4K up to 120p.
Are the K-3 Mark III and Alpha 9 III weather sealed?
K-3 Mark III: Yes. Alpha 9 III: Yes.
Which has better battery life?
Rated battery life is 640 shots (CIPA) for the K-3 Mark III and 400 shots for the Alpha 9 III, giving the K-3 Mark III the edge.
How much does each cost?
K-3 Mark III launched at $1,999 and Alpha 9 III at $5,999. The K-3 Mark III is $4,000 less.
Can't decide between two? Compare a third camera.
Add any camera to get a three-way K-3 Mark III vs Alpha 9 III vs X comparison.
Specs sourced from manufacturer data. Use-case scores algorithmically derived. Last reviewed July 2026.