Pentax
K-3 Mark III
APS-C DSLR flagship with optical viewfinder and weather sealing.
$1,999
Launch priceReleased Apr 2021
Ricoh
GR III
Street photography icon with 24.24MP APS-C, 28mm equivalent GR lens, 3-axis SR, and snap-focus in a pocket body.
$899
Launch priceReleased Mar 2019
K-3 Mark III is 2.1 years newer.
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Wins
K-3 Mark III
Wins
GR III
2 categories tied
TL;DR — Key differences
- AK-3 Mark III has higher Burst (electronic) (20 fps vs 4 fps)
- BGR III has higher ISO max (native) (102,400 vs 25,600)
- AK-3 Mark III has higher Battery life (CIPA) (640 shots vs 200 shots)
- AK-3 Mark III has higher AF points / zones (101 vs 49)
- BGR III has lower Weight (257 g vs 520 g)
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)
GR III
109 × 62 × 33 mm
257 g (0.57 lb / 9.07 oz)
K-3 Mark III is 29mm wider, 36mm taller, and 55mm thicker than GR III.
K-3 Mark III is 263 g heavier than GR III.
Depth (front-to-back): 88mm K-3 Mark III · 33mm GR III
Sensor size, to scale
K-3 Mark III
23.5 × 15.6 mm · APS-C
367 mm² area
GR III
23.5 × 15.6 mm · APS-C
367 mm² area
Lens ecosystem
Native lens selection
K-3 Mark III
✓ more lensesPentax K
70+
native lenses available
GR III: 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 200 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 III
Subject recognition
Adds Face, Eye
Codecs
Adds MPEG-4 AVC/H.264, MOV
Dimensions (W×H×D mm)
Adds 109.4, 61.9, 33.2
Card types
Adds SD, SDHC, SDXC UHS-I
ISO max (native)
102,400 vs 25,600 — higher is better
Weight
257 g vs 520 g — lower is better
Both cameras share
- ✓ISO min (native) — Both 100
- ✓Eye AF — Both support eye af
- ✓4K max frame rate — Both 60 fps
- ✓In-body stabilization — Both support in-body stabilization
- ✓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 III
Pros
- ✓Pocketable APS-C
- ✓28mm equivalent GR lens
- ✓3-axis sensor-shift SR
- ✓Snap focus street shooting
Cons
- –Fixed lens
- –No built-in EVF
- –Full HD video only
Decided which one is right for you?
Compare live prices for the K-3 Mark III and GR III at major authorized retailers.
Pentax K-3 Mark III
Ricoh GR III
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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 III?
K-3 Mark III scores 10.0/10 versus 2.0/10 for GR III — 20fps burst captures fleeting moments.
What's the resolution difference between the K-3 Mark III and GR III?
K-3 Mark III is 25.7 MP and GR III is 24.24 MP, so the K-3 Mark III captures more detail for cropping and large prints.
Do the K-3 Mark III and GR III have in-body image stabilization?
K-3 Mark III has 7-stop in-body image stabilization, while gR III has in-body image stabilization.
Which shoots faster bursts — the K-3 Mark III or the GR III?
K-3 Mark III reaches 20 fps electronic. GR III reaches 4 fps electronic.
What's the weight difference between the K-3 Mark III and GR III?
K-3 Mark III weighs 520 g and GR III weighs 257 g, so the GR III is 263 g lighter.
Do the K-3 Mark III and GR III record 4K video?
K-3 Mark III: 4K up to 60p. GR III: 4K up to 60p.
Are the K-3 Mark III and GR III weather sealed?
K-3 Mark III: Yes. GR III: No.
Which has better battery life?
Rated battery life is 640 shots (CIPA) for the K-3 Mark III and 200 shots for the GR III, giving the K-3 Mark III the edge.
How much does each cost?
K-3 Mark III launched at $1,999 and GR III at $899. The GR III is $1,100 less.
Specs sourced from manufacturer data. Use-case scores algorithmically derived. Last reviewed May 2026.