Pentax
K-3 Mark III
APS-C DSLR flagship with optical viewfinder and weather sealing.
$1,999
Released Apr 2021
Sony
Alpha 1 II
50MP stacked flagship with 30fps RAW, 8K video, and Sony's fastest hybrid performance.
$6,499
Released Nov 2024
Alpha 1 II is 3.6 years newer.
Wins
K-3 Mark III
Wins
Alpha 1 II
3 categories tied
TL;DR — Key differences
- BAlpha 1 II has higher AF points / zones (759 vs 101)
- BAlpha 1 II has higher EVF resolution (9,437,184 vs 3,690,000)
- BAlpha 1 II has higher 4K max frame rate (120 fps vs 60 fps)
- BAlpha 1 II has higher EVF refresh rate (240 Hz vs 120 Hz)
- BAlpha 1 II has higher Resolution (50.1 MP vs 25.7 MP)
Key specs at a glance
Size and weight, to scale
K-3 Mark III
138 × 98 × 88 mm
520 g (1.15 lb / 18.34 oz)
Alpha 1 II
136 × 97 × 83 mm
743 g (1.64 lb / 26.21 oz)
K-3 Mark III is 2mm wider, 1mm taller, and 5mm thicker than Alpha 1 II.
K-3 Mark III is 223 g lighter than Alpha 1 II.
Depth (front-to-back): 88mm K-3 Mark III · 83mm Alpha 1 II
Sensor size, to scale
K-3 Mark III
23.5 × 15.6 mm · APS-C
367 mm² area
Alpha 1 II
35.9 × 24 mm · Full Frame
862 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 1 II
✓ 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
Dimensions (W×H×D mm)
Adds 138, 98, 88
Weight
520 g vs 743 g — lower is better
Subject recognition
Adds Vehicle
Battery life (CIPA)
640 shots vs 520 shots — higher is better
AF frame coverage
100 % vs 94 % — higher is better
Reasons to choose
Alpha 1 II
AF low-light limit
-4 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
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 1 II supports it
Subject recognition
Adds Insect, Car/Train, Airplane
4K max frame rate
120 fps vs 60 fps — higher is better
Both cameras share
- ✓ISO min (native) — 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
- ✓Max video bit rate — Both 150 Mbps
- ✓In-body stabilization — Both support in-body stabilization
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 1 II
Pros
- ✓50MP stacked sensor
- ✓30fps blackout-free burst
- ✓8K 30p video
- ✓Best Sony AF
Cons
- –Very expensive
- –Complex menus
- –Large files
Full specifications
✓ = category winner
Frequently asked
Quick answers generated from verified specs.
Which is better for landscape, K-3 Mark III or Alpha 1 II?
Alpha 1 II scores 9.0/10 versus 5.0/10 for K-3 Mark III — 50.1MP — massive detail for large prints.
What's the resolution difference between the K-3 Mark III and Alpha 1 II?
K-3 Mark III is 25.7 MP and Alpha 1 II is 50.1 MP, so the Alpha 1 II captures more detail for cropping and large prints.
Do the K-3 Mark III and Alpha 1 II have in-body image stabilization?
K-3 Mark III has 7-stop in-body image stabilization, while alpha 1 II has 8.5-stop in-body image stabilization.
Which shoots faster bursts — the K-3 Mark III or the Alpha 1 II?
K-3 Mark III reaches 20 fps electronic. Alpha 1 II reaches 30 fps electronic.
What's the weight difference between the K-3 Mark III and Alpha 1 II?
K-3 Mark III weighs 520 g and Alpha 1 II weighs 743 g, so the K-3 Mark III is 223 g lighter.
Do the K-3 Mark III and Alpha 1 II record 4K video?
K-3 Mark III: 4K up to 60p. Alpha 1 II: 8K (max), 4K up to 120p.
Are the K-3 Mark III and Alpha 1 II weather sealed?
K-3 Mark III: Yes. Alpha 1 II: Yes.
Which has better battery life?
Rated battery life is 640 shots (CIPA) for the K-3 Mark III and 520 shots for the Alpha 1 II, giving the K-3 Mark III the edge.
How much does each cost?
K-3 Mark III launched at $1,999 and Alpha 1 II at $6,499. The K-3 Mark III is $4,500 less.
Specs sourced from manufacturer data. Use-case scores algorithmically derived. Last reviewed May 2026.
Product images courtesy of Pentax and Sony press materials.