Pentax
K-3 Mark III
APS-C DSLR flagship with optical viewfinder and weather sealing.
$1,999
Launch priceReleased Apr 2021
Ricoh
GR IVx
40mm-equivalent GR IV sibling with a newly designed 26.1mm f/2.8 lens, 25.74MP APS-C sensor, 5-axis SR, 4K video, 53GB internal storage, and pocket street-camera handling. Winter 2026 planned.
$1,499
Launch priceReleased Dec 2026
GR IVx is 5.6 years newer.
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Wins
K-3 Mark III
Wins
GR IVx
2 categories tied
Which would you choose?
TL;DR — Key differences
- BGR IVx has higher ISO max (native) (204,800 vs 25,600)
- AK-3 Mark III has higher Burst (electronic) (20 fps vs 4 fps)
- AK-3 Mark III has higher Battery life (CIPA) (640 shots vs 250 shots)
- AK-3 Mark III has higher AF points / zones (101 vs 49)
- AK-3 Mark III has higher Burst (mechanical) (8 fps vs 4 fps)
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
GR IVx
109 × 61 × 33 mm
265 g (0.58 lb / 9.35 oz)
K-3 Mark III is 29mm wider, 37mm taller, and 55mm thicker than GR IVx.
K-3 Mark III is 255 g heavier than GR IVx.
Depth (front-to-back): 88mm K-3 Mark III · 33mm GR IVx
Sensor size, to scale
K-3 Mark III
23.5 × 15.6 mm · APS-C
367 mm² area
GR IVx
23.3 × 15.5 mm · APS-C
361 mm² area
Lens ecosystem
Native lens selection
K-3 Mark III
✓ more lensesPentax K
70+
native lenses available
GR IVx: mount data unavailable
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
Subject recognition
Adds Human, Animal, Bird…
Codecs
Adds H.265, H.264
Dimensions (W×H×D mm)
Adds 138, 98, 88
Card types
Adds SD UHS-II
Burst (electronic)
20 fps vs 4 fps — higher is better
Battery life (CIPA)
640 shots vs 250 shots — higher is better
AF points / zones
101 vs 49 — higher is better
Animal / bird AF
Only K-3 Mark III supports it
Reasons to choose
GR IVx
Subject recognition
Adds Face, Eye
Codecs
Adds MPEG-4 AVC/H.264, MOV
Dimensions (W×H×D mm)
Adds 109.4, 61.1, 33.4
Card types
Adds microSD, microSDHC, microSDXC UHS-I
ISO max (native)
204,800 vs 25,600 — higher is better
Weight
265 g vs 520 g — lower is better
Resolution
25.74 MP vs 25.7 MP — higher is better
Both cameras share
- ✓ISO min (native) — Both 100
- ✓Eye AF — Both support eye af
- ✓Max video bit rate — Both 150 Mbps
- ✓In-body stabilization (IBIS) — Both support in-body stabilization (ibis)
- ✓Touchscreen — Both support touchscreen
- ✓Wi-Fi — Both support wi-fi
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
GR IVx
Pros
- ✓New 26.1mm f/2.8 GR lens (40mm equiv.)
- ✓GR IV 25.74MP APS-C + 5-axis SR
- ✓4K 30p/24p and 53GB built-in storage
- ✓Snap focus, 50/71mm crops, 2-stop ND
- ✓Pocketable 265g body
Cons
- –Price not yet announced (listed at GR IV $1,499)
- –Winter 2026 or later — still in development as of Aug 2026
- –No built-in EVF
- –Fixed 40mm-equiv. lens
Decided which one is right for you?
Compare live prices for the K-3 Mark III and GR IVx at major authorized retailers.
Pentax K-3 Mark III
Ricoh GR IVx
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Full specifications
✓ = category winner
Frequently asked
Quick answers generated from verified specs.
Which is better for wildlife, K-3 Mark III or GR IVx?
K-3 Mark III scores 10.0/10 versus 1.0/10 for GR IVx — 20fps burst captures fleeting moments.
What's the resolution difference between the K-3 Mark III and GR IVx?
K-3 Mark III is 25.7 MP and GR IVx is 25.74 MP, so the GR IVx captures more detail for cropping and large prints.
Do the K-3 Mark III and GR IVx have in-body image stabilization?
K-3 Mark III has 7-stop in-body image stabilization, while GR IVx has in-body image stabilization.
Which shoots faster bursts — the K-3 Mark III or the GR IVx?
K-3 Mark III reaches 20 fps electronic. GR IVx reaches 4 fps electronic.
What's the weight difference between the K-3 Mark III and GR IVx?
K-3 Mark III weighs 520 g and GR IVx weighs 265 g, so the GR IVx is 255 g lighter.
Do the K-3 Mark III and GR IVx record 4K video?
K-3 Mark III: 4K up to 60p. GR IVx: 4K up to 30p.
Are the K-3 Mark III and GR IVx weather sealed?
K-3 Mark III: Yes. GR IVx: No.
Which has better battery life?
Rated battery life is 640 shots (CIPA) for the K-3 Mark III and 250 shots for the GR IVx, giving the K-3 Mark III the edge.
How much does each cost?
K-3 Mark III launched at $1,999 and GR IVx at $1,499. The GR IVx is $500 less.
Can't decide between two? Compare a third camera.
Add any camera to get a three-way K-3 Mark III vs GR IVx vs X comparison.
Specs sourced from manufacturer data. Use-case scores algorithmically derived. Last reviewed November 2026.
Product images courtesy of Pentax and Ricoh press materials.