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lensmount

Head-to-head · Sony A → Sony E

Sony LA-EA3 vs LA-EA4 — thin passthrough or SLT mirror adapter

Both adapt Sony A-mount lenses onto E-mount bodies, and both predate the LA-EA5. The LA-EA4 (2014) packs an SLT mirror, a 15-point AF sensor, and a screw-drive motor, so it autofocuses any A-mount lens on any E body. The LA-EA3 (2013) is a thin pass-through that loses no light and gives full sensor-wide AF on a modern body — but only on SSM / SAM lenses.

Side-by-side specifications

SpecSony LA-EA3
Sony · 2013
Sony LA-EA4
Sony · 2014
Lens sideSony ASony A
Body sideSony ESony E
Release year20132014
Body-side contacts9 pins9 pins
Firmware-updatableNoNo
Weather-sealedNoNo
Has glass (focal reducer)NoNo

Differences that matter

AF architecture is the headline split. The LA-EA4 is self-contained: an internal SLT (Single-Lens Translucent) mirror module plus a dedicated 15-point phase-detect AF sensor plus a screw-drive motor, so it autofocuses every A-mount lens — including legacy screw-drive Minolta and early Sony glass — on any E body. The LA-EA3 has no mirror, no AF sensor, and no motor: it is a pure electronic pass-through that relies on the body's own on-sensor PDAF and drives only SSM / SAM (in-lens-motor) A-mount lenses. Screw-drive lenses are manual-focus-only on the LA-EA3 because nothing turns the screw.

Light loss is the LA-EA4's standing cost: the translucent mirror splits incoming light between the imaging sensor and the in-adapter AF sensor, taking roughly ⅓ stop on every frame, stills or video, whether or not you're autofocusing. The LA-EA3 passes 100% of the light to the sensor — no penalty.

AF quality on a modern body favours the LA-EA3 decisively when your glass is SSM / SAM. On an a7 III, a7 IV, a7R V or a1 the LA-EA3 inherits the body's full sensor-wide PDAF (hundreds of points) with Eye AF and subject tracking, while the LA-EA4 is locked to its older, fixed 15-point pattern shared with Sony's A-mount DSLRs — a much smaller, sparser AF area that predates Real-Time Tracking.

Body compatibility is the LA-EA4's standing advantage. Because its AF is entirely self-contained, the LA-EA4 delivers the same phase-detect AF on every E body — a6000, NEX, a7 / a7 II, a7S original — that lack the on-sensor PDAF the LA-EA3 needs to focus at all. On those older bodies the LA-EA3 cannot autofocus reliably even on SSM / SAM glass, so the LA-EA4 is the only one of the two that works.

Size and weight: the LA-EA3 is ~115 g lighter and noticeably shorter, with no mirror box or motor housing. The LA-EA4 is the bulkiest Sony A→E adapter to carry unmounted.

Both predate — and are largely superseded by — the LA-EA5 (2020), which marries the LA-EA3's mirrorless, no-light-loss pass-through design to an internal screw-drive motor that leans on the body's PDAF. On a modern PDAF body the LA-EA5 is the better pick than either of these two; the LA-EA3-vs-LA-EA4 decision matters most when you're buying second-hand on a budget or shooting an older E body the LA-EA5 can't serve.

When to pick which

Pick the

Sony LA-EA3 when

  • Your A-mount kit is exclusively SSM / SAM (in-lens motor) — Sony 70-200 f/2.8 G SSM, 16-35 f/2.8 ZA SSM, Sigma HSM A-mount.
  • You shoot on a modern PDAF E-mount body (a7 III or later) and want full sensor-wide AF, Eye AF, and tracking rather than the LA-EA4's fixed 15-point pattern.
  • Light loss and weight matter — the LA-EA3 keeps the full ⅓ stop the LA-EA4's mirror gives up, and saves ~115 g.

Pick the

Sony LA-EA4 when

  • Your A-mount kit includes screw-drive Minolta AF or early Sony A-mount lenses (50 f/1.7, Beercan zooms) and you want them to autofocus — only the LA-EA4 has the internal motor here.
  • You shoot on an older E body without usable LA-EA3 PDAF — a6000, NEX, a7 / a7 II, a7S original — where the LA-EA4's self-contained SLT AF is the only one of the two that focuses at all.
  • You want deterministic, body-independent 15-point AF behaviour for controlled studio work.

Common questions

Which one autofocuses my screw-drive Minolta Maxxum 50 f/1.7?
The LA-EA4 — it has an internal screw-drive motor (and its own SLT mirror + 15-point AF sensor). The LA-EA3 has no motor, so screw-drive Minolta and early Sony A-mount lenses are manual-focus-only on it. If you're on a modern PDAF body and want screw-drive AF in a lighter package, the LA-EA5 is the newer alternative.
I'm on an older E body like the a6000 or a7 II — which should I get?
The LA-EA4. Its AF is self-contained (SLT mirror + 15-point sensor), so it delivers phase-detect AF on E bodies that can't drive an adapted A-mount lens themselves. The LA-EA3 depends on the body's on-sensor PDAF and cannot autofocus reliably on these older bodies.
On an a7 IV with only SSM / SAM lenses, is the LA-EA3 or LA-EA4 better?
The LA-EA3. With in-lens-motor (SSM / SAM) glass it gives full sensor-wide PDAF with Eye AF and tracking, loses no light, and weighs ~115 g less. The LA-EA4's mirror costs ⅓ stop and its 15-point AF is a downgrade on a modern body. If you might later add screw-drive glass, consider the LA-EA5 instead.
Are the LA-EA3 and LA-EA4 still worth buying in 2026?
Both predate the LA-EA5, which supersedes them on any modern PDAF body. The LA-EA4 is winding down at retail; the LA-EA3 remains available. Choose between these two mainly when buying second-hand on a budget, or when an older E body rules the LA-EA5 out — in which case the LA-EA4's self-contained AF is the safer bet.

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