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Sigma 100-400mm DG DN OS — Prime/zoom
Sigma

Sigma 100-400mm DG DN OS

Prime/zoom

86
/ 100
From $999
VS
Sony FE 85mm f/1.8 — Prime/Zoom
Sony

Sony FE 85mm f/1.8

Prime/Zoom

86
/ 100
From $598
Specdex verdict

Dead heat — it comes down to priorities.

In our weighted Specdex score, Sigma 100-400mm DG DN OS lands at 86 and Sony FE 85mm f/1.8 at 86. With scores tied, the decision hinges on which sub-scores matter most to you.

Pick Sigma 100-400mm DG DN OS if…

  • ✓Proven optical formula
  • ✓Weather-sealing (L/GM/S)
  • ✓Strong resale

Pick Sony FE 85mm f/1.8 if…

  • ✓Fast aperture
  • ✓Quiet autofocus
  • ✓Weather-sealed (most)
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Winner by scenario

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

Build

Sigma 100-400mm DG DN OS

Compared on the build sub-score

Sigma 100-400mm DG DN OS leads on build (90 vs 88).

Sharpness

Tie

Compared on the sharpness sub-score

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

Autofocus

Sony FE 85mm f/1.8

Compared on the autofocus sub-score

Sony FE 85mm f/1.8 leads on af (84 vs 82).

Value for money

Sony FE 85mm f/1.8

Specdex score per dollar at MSRP

Sony FE 85mm f/1.8 more score per dollar ($598 vs $999).

Sigma 100-400mm DG DN OS 86
vs
86 Sony FE 85mm f/1.8

Score breakdown

Sigma 100-400mm DG DN OS
86
sharpness 86
af 82
build 90
value 86
Sony FE 85mm f/1.8
86
sharpness 86
af 84
build 88
value 85

Specs side-by-side

Sigma 100-400mm DG DN OS versus Sony FE 85mm f/1.8 — full spec comparison
Spec Sigma 100-400mm DG DN OS Sony FE 85mm f/1.8

Sigma 100-400mm DG DN OS

Pros
  • +Proven optical formula
  • +Weather-sealing (L/GM/S)
  • +Strong resale
Cons
  • −Mount-specific
  • −Older AF motor on some
  • −Heavier than modern counterparts

Sony FE 85mm f/1.8

Pros
  • +Fast aperture
  • +Quiet autofocus
  • +Weather-sealed (most)
Cons
  • −Mount-specific
  • −Weight varies
  • −Price scales with quality

FAQ: Sigma 100-400mm DG DN OS vs Sony FE 85mm f/1.8

Which is better, Sigma 100-400mm DG DN OS or Sony FE 85mm f/1.8? +

Both score 86 on our weighted rubric — tied. Your best pick depends on the sub-scores above.

Is Sigma 100-400mm DG DN OS worth the price? +

At $999, Sigma 100-400mm DG DN OS delivers a Specdex score of 86 — strongest in build.

Is Sony FE 85mm f/1.8 worth the price? +

At $598, Sony FE 85mm f/1.8 delivers a Specdex score of 86 — strongest in build.

Does Sigma 100-400mm DG DN OS or Sony FE 85mm f/1.8 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 build, Sigma 100-400mm DG DN OS or Sony FE 85mm f/1.8? +

Sigma 100-400mm DG DN OS — leads on build (90 vs 88). Compared on the build sub-score.

Which is better for autofocus, Sigma 100-400mm DG DN OS or Sony FE 85mm f/1.8? +

Sony FE 85mm f/1.8 — leads on af (84 vs 82). Compared on the autofocus sub-score.