Pentax
645Z
51MP medium format DSLR that made digital MF accessible — still prized for landscape and studio.
$8,499
Launch priceReleased Apr 2014
Pentax
K-3 Mark III Monochrome
Monochrome-only APS-C DSLR with 25.7MP sensor, IBIS, optical viewfinder, and weather sealing.
$2,199
Launch priceReleased Apr 2024
K-3 Mark III Monochrome is 10 years newer.
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Wins
645Z
Wins
K-3 Mark III Monochrome
14 categories tied
Which would you choose?
TL;DR — Key differences
- A645Z has higher Resolution (51.4 MP vs 25.7 MP)
- BK-3 Mark III Monochrome has lower Weight (820 g vs 1470 g)
- A645Z has lower ISO min (native) (64 vs 100)
- A645Z has higher IBIS effectiveness (7 stops vs 5.5 stops)
Key specs at a glance
Size and weight, to scale
📸 Snap this size diff to share645Z
156 × 117 × 123 mm
1470 g (3.24 lb / 51.85 oz)
Credit card
85.6 × 54 mm
for scale
K-3 Mark III Monochrome
135 × 104 × 74 mm
820 g (1.81 lb / 28.92 oz)
645Z is 22mm wider, 14mm taller, and 50mm thicker than K-3 Mark III Monochrome.
645Z is 650 g heavier than K-3 Mark III Monochrome.
Depth (front-to-back): 123mm 645Z · 74mm K-3 Mark III Monochrome
Sensor size, to scale
645Z
43.8 × 32.8 mm · Medium Format
1437 mm² area
K-3 Mark III Monochrome
23.5 × 15.6 mm · APS-C
367 mm² area
3.9× larger sensor area = shallower depth of field and better low-light performance.
Lens ecosystem
Native lens selection
645Z: mount data unavailable
K-3 Mark III Monochrome
✓ more lensesPentax K
70+
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
645Z
Dimensions (W×H×D mm)
Adds 156, 117, 123
Resolution
51.4 MP vs 25.7 MP — higher is better
AA filter
Only 645Z supports it
ISO min (native)
64 vs 100 — lower is better
IBIS effectiveness
7 stops vs 5.5 stops — higher is better
Reasons to choose
K-3 Mark III Monochrome
Dimensions (W×H×D mm)
Adds 134.5, 103.5, 73.5
Weight
820 g vs 1470 g — lower is better
Both cameras share
- ✓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
- ✓Burst (mechanical) — Both 8 fps
Pros & cons at a glance
Editorially curated highlights and trade-offs.
645Z
Pros
- ✓51MP medium format
- ✓CMOS sensor
- ✓Pentax color
- ✓Relatively affordable MF
Cons
- –Huge body
- –Slow operation
- –Limited lens line vs Hasselblad
K-3 Mark III Monochrome
Pros
- ✓Dedicated monochrome sensor
- ✓Optical viewfinder
- ✓IBIS in a DSLR
- ✓Weather sealed
Cons
- –Black-and-white only
- –DSLR platform
- –Limited video
Decided which one is right for you?
Compare live prices for the 645Z and K-3 Mark III Monochrome at major authorized retailers.
Pentax 645Z
Pentax K-3 Mark III Monochrome
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Full specifications
✓ = category winner
Frequently asked
Quick answers generated from verified specs.
Which is better for landscape, 645Z or K-3 Mark III Monochrome?
645Z scores 8.0/10 versus 5.0/10 for K-3 Mark III Monochrome — 51.4MP — massive detail for large prints.
What's the resolution difference between the 645Z and K-3 Mark III Monochrome?
645Z is 51.4 MP and K-3 Mark III Monochrome is 25.7 MP, so the 645Z captures more detail for cropping and large prints.
Do the 645Z and K-3 Mark III Monochrome have in-body image stabilization?
645Z has 7-stop in-body image stabilization, while K-3 Mark III Monochrome has 5.5-stop in-body image stabilization.
Which shoots faster bursts — the 645Z or the K-3 Mark III Monochrome?
645Z reaches 20 fps electronic. K-3 Mark III Monochrome reaches 20 fps electronic.
What's the weight difference between the 645Z and K-3 Mark III Monochrome?
645Z weighs 1470 g and K-3 Mark III Monochrome weighs 820 g, so the K-3 Mark III Monochrome is 650 g lighter.
Do the 645Z and K-3 Mark III Monochrome record 4K video?
645Z: 4K up to 60p. K-3 Mark III Monochrome: 4K up to 60p.
Are the 645Z and K-3 Mark III Monochrome weather sealed?
645Z: Yes. K-3 Mark III Monochrome: Yes.
Which has better battery life?
Rated battery life is 640 shots (CIPA) for the 645Z and 640 shots for the K-3 Mark III Monochrome, giving the K-3 Mark III Monochrome the edge.
How much does each cost?
645Z launched at $8,499 and K-3 Mark III Monochrome at $2,199. The K-3 Mark III Monochrome is $6,300 less.
Can't decide between two? Compare a third camera.
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Specs sourced from manufacturer data. Use-case scores algorithmically derived. Last reviewed June 2026.