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Pentax K-3 Mark III — APS-C DSLR · 2021
Pentax

Pentax K-3 Mark III

APS-C DSLR · 2021

80
/ 100
From $1,999
VS
Sony A7S III wins by 11
Sony A7S III — full-frame · 2020
Sony

Sony A7S III

full-frame · 2020

91
/ 100
From $3,498
Specdex verdict

Sony A7S III takes it — here’s why.

In our weighted Specdex score, Pentax K-3 Mark III lands at 80 and Sony A7S III at 91. That puts Sony A7S III ahead by 11 points — a decisive margin driven mostly by its strengths in the categories below.

Pick Pentax K-3 Mark III if…

  • ✓Mature system, great used market
  • ✓Proven lens lineup
  • ✓Often on sale

Pick Sony A7S III if…

  • ✓Current-gen AF system
  • ✓Proven lens ecosystem
  • ✓Strong video + stills balance
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Winner by scenario

Derived from the sub-score breakdown · not a separate test

Ergonomics

Tie

Compared on the ergonomics sub-score

Effectively tied — neither pulls a 2-point weighted lead.

Photo

Sony A7S III

Compared on the photo sub-score

Sony A7S III leads on photo (91 vs 80).

Autofocus

Sony A7S III

Compared on the autofocus sub-score

Sony A7S III leads on autofocus (89 vs 76).

Value for money

Pentax K-3 Mark III

Specdex score per dollar at MSRP

Pentax K-3 Mark III more score per dollar ($1,999 vs $3,498).

Pentax K-3 Mark III 80
vs
91 Sony A7S III

Score breakdown

Pentax K-3 Mark III
80
photo 80
video 72
autofocus 76
ergonomics 86
Sony A7S III
91
photo 91
video 87
autofocus 89
ergonomics 86

Specs side-by-side

Pentax K-3 Mark III versus Sony A7S III — full spec comparison
Spec Pentax K-3 Mark III Sony A7S III
Format
APS-C DSLR
full-frame
Release year
2021
2020

Pentax K-3 Mark III

Pros
  • +Mature system, great used market
  • +Proven lens lineup
  • +Often on sale
Cons
  • −Older AF system
  • −Heavier than modern mirrorless
  • −Firmware updates trailed off

Sony A7S III

Pros
  • +Current-gen AF system
  • +Proven lens ecosystem
  • +Strong video + stills balance
Cons
  • −Body price excludes lens
  • −Heavy for travel (flagship)
  • −Learning curve on menus

FAQ: Pentax K-3 Mark III vs Sony A7S III

Which is better, Pentax K-3 Mark III or Sony A7S III? +

Sony A7S III scores 91 on our weighted rubric — ahead by 11. Your best pick depends on the sub-scores above.

Is Pentax K-3 Mark III worth the price? +

At $1,999, Pentax K-3 Mark III delivers a Specdex score of 80 — strongest in ergonomics.

Is Sony A7S III worth the price? +

At $3,498, Sony A7S III delivers a Specdex score of 91 — strongest in photo.

Does Pentax K-3 Mark III or Sony A7S III last longer? +

Based on our long-term update and support ratings, both ship with multi-year support. Battery and reliability scores are visible in the breakdown above.

Which is better for photo, Pentax K-3 Mark III or Sony A7S III? +

Sony A7S III — leads on photo (91 vs 80). Compared on the photo sub-score.

Which is better for autofocus, Pentax K-3 Mark III or Sony A7S III? +

Sony A7S III — leads on autofocus (89 vs 76). Compared on the autofocus sub-score.