Pentax
K-3 Mark III
APS-C DSLR flagship with optical viewfinder and weather sealing.
$1,999
Released Apr 2021
Sony
Alpha 7 IV
33MP hybrid all-rounder with 10-bit 4K 60p and AI-powered subject tracking.
$2,499
Released Oct 2021
Alpha 7 IV is 6 months newer.
Wins
K-3 Mark III
Wins
Alpha 7 IV
5 categories tied
TL;DR — Key differences
- BAlpha 7 IV has higher AF points / zones (759 vs 101)
- BAlpha 7 IV has higher RAW buffer depth (828 frames vs 120 frames)
- BAlpha 7 IV has higher Max video bit rate (600 Mbps vs 150 Mbps)
- BAlpha 7 IV has higher ISO max (native) (51,200 vs 25,600)
- AK-3 Mark III has higher Burst (electronic) (20 fps vs 10 fps)
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 7 IV
131 × 96 × 80 mm
658 g (1.45 lb / 23.21 oz)
K-3 Mark III is 7mm wider, 2mm taller, and 8mm thicker than Alpha 7 IV.
K-3 Mark III is 138 g lighter than Alpha 7 IV.
Depth (front-to-back): 88mm K-3 Mark III · 80mm Alpha 7 IV
Sensor size, to scale
K-3 Mark III
23.5 × 15.6 mm · APS-C
367 mm² area
Alpha 7 IV
35.9 × 23.9 mm · Full Frame
858 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 7 IV
✓ 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
Burst (electronic)
20 fps vs 10 fps — higher is better
Pre-Capture / Pre-Release
Only K-3 Mark III supports it
Subject recognition
Adds Vehicle
IBIS effectiveness
7 stops vs 5.5 stops — higher is better
Weight
520 g vs 658 g — lower is better
Battery life (CIPA)
640 shots vs 580 shots — higher is better
AF frame coverage
100 % vs 94 % — higher is better
Reasons to choose
Alpha 7 IV
AF low-light limit
-4 EV vs -3 EV — lower is better
Dimensions (W×H×D mm)
Adds 131.3, 96.4, 79.8
AF points / zones
759 vs 101 — higher is better
RAW buffer depth
828 frames vs 120 frames — higher is better
Max video bit rate
600 Mbps vs 150 Mbps — higher is better
Codecs
Adds XAVC HS, XAVC S, XAVC S-I
AA filter
Only Alpha 7 IV supports it
ISO max (native)
51,200 vs 25,600 — 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
- ✓4K max frame rate — Both 60 fps
- ✓In-body stabilization — Both support in-body stabilization
- ✓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 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
Full specifications
✓ = category winner
Frequently asked
Quick answers generated from verified specs.
Which is better for portraits, K-3 Mark III or Alpha 7 IV?
Alpha 7 IV scores 9.0/10 versus 6.5/10 for K-3 Mark III — 33MP — ample resolution for portraits.
What's the resolution difference between the K-3 Mark III and Alpha 7 IV?
K-3 Mark III is 25.7 MP and Alpha 7 IV is 33 MP, so the Alpha 7 IV captures more detail for cropping and large prints.
Do the K-3 Mark III and Alpha 7 IV have in-body image stabilization?
K-3 Mark III has 7-stop in-body image stabilization, while alpha 7 IV has 5.5-stop in-body image stabilization.
Which shoots faster bursts — the K-3 Mark III or the Alpha 7 IV?
K-3 Mark III reaches 20 fps electronic. Alpha 7 IV reaches 10 fps electronic.
What's the weight difference between the K-3 Mark III and Alpha 7 IV?
K-3 Mark III weighs 520 g and Alpha 7 IV weighs 658 g, so the K-3 Mark III is 138 g lighter.
Do the K-3 Mark III and Alpha 7 IV record 4K video?
K-3 Mark III: 4K up to 60p. Alpha 7 IV: 4K up to 60p.
Are the K-3 Mark III and Alpha 7 IV weather sealed?
K-3 Mark III: Yes. Alpha 7 IV: Yes.
Which has better battery life?
Rated battery life is 640 shots (CIPA) for the K-3 Mark III and 580 shots for the Alpha 7 IV, giving the K-3 Mark III the edge.
How much does each cost?
K-3 Mark III launched at $1,999 and Alpha 7 IV at $2,499. The K-3 Mark III is $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.