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Pentax

K-3 Mark III

APS-C DSLR flagship with optical viewfinder and weather sealing.

$1,999

Launch price

Released Apr 2021

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vs

Pentax

K-5

Legendary weather-sealed APS-C DSLR with 16MP sensor and exceptional build quality.

$1,099

Launch price

Released Sep 2010

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K-3 Mark III is 10.6 years newer.

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Wins

7categories

K-3 Mark III

★ Wildlife★ Travel

Wins

0categories

K-5

★ Wildlife★ Sports & Action

11 categories tied

Which would you choose?

TL;DR — Key differences

K-3 Mark III wins 5 categories·K-5 wins 0 categories
  • AK-3 Mark III has higher RAW buffer depth (120 frames vs 60 frames)
  • AK-3 Mark III has higher Resolution (25.7 MP vs 16.3 MP)
  • AK-3 Mark III has higher EVF resolution (3,690,000 vs 2,360,000)
  • AK-3 Mark III has lower Weight (520 g vs 750 g)
  • AK-3 Mark III has higher Burst (mechanical) (8 fps vs 6 fps)

Key specs at a glance

K-3 Mark IIIK-5
Resolution25.7 MP16.3 MP
SensorAPS-CAPS-C
ISO max25,60025,600
Burst20 fps15 fps
4K60 fps60 fps
IBIS7-stop6-stop
Weight520 g750 g
Battery640 shots640 shots

Size and weight, to scale

K-3 Mark III

138 × 98 × 88 mm

520 g (1.15 lb / 18.34 oz)

Credit card shown to scale as a size reference (ISO 7810, 85.6 × 54 mm)

Credit card

85.6 × 54 mm

for scale

K-5

131 × 97 × 73 mm

750 g (1.65 lb / 26.46 oz)

K-3 Mark III is 7mm wider, 1mm taller, and 15mm thicker than K-5.

K-3 Mark III is 230 g lighter than K-5.

Depth (front-to-back): 88mm K-3 Mark III · 73mm K-5

Sensor size, to scale

K-3 Mark III

23.5 × 15.6 mm · APS-C

367 mm² area

K-5

23.7 × 15.7 mm · APS-C

372 mm² area

Lens ecosystem

Native lens selection

K-3 Mark III

✓ more lenses

Pentax K

70+

native lenses available

30 first-party40 third-party

K-5

✓ more lenses

Pentax K

70+

native lenses available

30 first-party40 third-party

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

Use caseK-3 Mark IIIK-5
Portrait
6.5Good✓ wins
5.5Fair
Sports & Action
6.5Good
6.5Good
Video & Hybrid
6.0Good
6.0Good
Landscape
5.0Fair✓ wins
3.5Limited
Travel
8.5Excellent✓ wins
6.5Good
Wildlife
10.0Excellent✓ wins
8.0Excellent
Vlogging
7.0Good✓ wins
5.5Fair

Why pick one over the other

Reasons to choose

K-3 Mark III

  • Dimensions (W×H×D mm)

    Adds 138, 98, 88

  • RAW buffer depth

    120 frames vs 60 frames — higher is better

  • Resolution

    25.7 MP vs 16.3 MP — higher is better

  • EVF resolution

    3,690,000 vs 2,360,000 — higher is better

  • Weight

    520 g vs 750 g — lower is better

  • Burst (mechanical)

    8 fps vs 6 fps — higher is better

  • Burst (electronic)

    20 fps vs 15 fps — higher is better

  • IBIS effectiveness

    7 stops vs 6 stops — higher is better

Reasons to choose

K-5

  • Dimensions (W×H×D mm)

    Adds 131, 97, 73

  • AA filter

    Only K-5 supports it

Both cameras share

  • ✓ISO min (native) — Both 100
  • ✓ISO max (native) — Both 25,600
  • ✓AF points / zones — Both 101
  • ✓AF frame coverage — Both 100 %
  • ✓Eye AF — Both support eye af
  • ✓Animal / bird AF — Both support animal / bird af

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

K-5

Pros

  • ✓Legendary build
  • ✓Weather sealed
  • ✓Excellent JPEG engine
  • ✓Compact pro DSLR

Cons

  • –16MP very dated
  • –Slow AF
  • –DSLR niche

Decided which one is right for you?

Compare live prices for the K-3 Mark III and K-5 at major authorized retailers.

Pentax K-3 Mark III

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Pentax K-5

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Full specifications

✓ = category winner

K-3 Mark III
K-5
Resolution
25.7 MP✓+58%
16.3 MP
Sensor type
APS-C CMOS
APS-C CMOS
Sensor size
23.5 × 15.6 mm
23.7 × 15.7 mm
AA filter
No
Yes
K-3 Mark III
K-5
Processor
Image processor
Image processor
K-3 Mark III
K-5
ISO min (native)
100
100
ISO max (native)
25,600
25,600
ISO max (expanded)
102,400
102,400
K-3 Mark III
K-5
Shutter type
Mechanical + Electronic
Mechanical + Electronic
Max mechanical speed
1/8000 sec
1/8000 sec
Max electronic speed
1/16000 sec
1/16000 sec

Frequently asked

Quick answers generated from verified specs.

Which is better for travel, K-3 Mark III or K-5?

K-3 Mark III scores 8.5/10 versus 6.5/10 for K-5 — 520g — compact and travel-friendly.

What's the resolution difference between the K-3 Mark III and K-5?

K-3 Mark III is 25.7 MP and K-5 is 16.3 MP, so the K-3 Mark III captures more detail for cropping and large prints.

Do the K-3 Mark III and K-5 have in-body image stabilization?

K-3 Mark III has 7-stop in-body image stabilization, while K-5 has 6-stop in-body image stabilization.

Which shoots faster bursts — the K-3 Mark III or the K-5?

K-3 Mark III reaches 20 fps electronic. K-5 reaches 15 fps electronic.

What's the weight difference between the K-3 Mark III and K-5?

K-3 Mark III weighs 520 g and K-5 weighs 750 g, so the K-3 Mark III is 230 g lighter.

Do the K-3 Mark III and K-5 record 4K video?

K-3 Mark III: 4K up to 60p. K-5: 4K up to 60p.

Are the K-3 Mark III and K-5 weather sealed?

K-3 Mark III: Yes. K-5: Yes.

Which has better battery life?

Rated battery life is 640 shots (CIPA) for the K-3 Mark III and 640 shots for the K-5, giving the K-5 the edge.

How much does each cost?

K-3 Mark III launched at $1,999 and K-5 at $1,099. The K-5 is $900 less.

Can't decide between two? Compare a third camera.

Add any camera to get a three-way K-3 Mark III vs K-5 vs X comparison.

Specs sourced from manufacturer data. Use-case scores algorithmically derived. Last reviewed June 2026.